Former NFL player Warren Sapp becomes emotional after being elected into the Pro Football Hall of Fame in this 2013 photo. Sapp was one of those who fell on hard times after retiring. (Photo by Stacy Revere/Getty Images) 
 
 Yes, NFL players work hard and bang heads all day long. But they can make a million bucks. 
 
 That, at least, is the brutal, but plausible trade-off facing thousands of players each season. 
 
 There's one big problem. The financial rewards of a professional football career often quickly vanish, according to new research published by the National Bureau of Economic Research. 
 
 According to the research, about one in six players file for bankruptcy within 12 years of leaving the league – and that’s despite the fact that a typical player earns about $3.2 million over his career. 
 
 Curiously, the likelihood of declaring bankruptcy doesn't seem to depend at all on how much money a player had earned. The stars were as likely as the scrubs to go broke. 
 
 “Having played for a long time and having been a successful and well-paid player does not provide much protection against the risk of going bankrupt,” according to the authors, Kyle Carlson, Joshua Kim, Annamaria Lusardi and Colin F. Camerer. 
 
 Here is their graph: 
 
 Exactly how many NFL players go broke has been a matter of intense speculation in recent years, especially as the bankruptcies of marquee players such as Warren Sapp and Vince Young became public. 
 
 One widely-cited article in Sports Illustrated estimated that 78 percent of former NFL players are bankrupt or under “financial stress” within two years of retirement. It is not clear from the article where that figure came from, however, and it does not seem to match the economists research, which was based on more than 2,000 players who were drafted by NFL teams from 1996 to 2003. They used public court records to find bankruptcy filings. 
 
 The economists found that only about two percent of NFL players filed for bankruptcy within two years. 
 
 "The result of our comprehensive research on bankruptcy risk among NFL players is quite different" from the Sports Illustrated estimate, they write. 
 
 The final curiosity of note is that while NFL players typically have career earnings of millions of dollars, they are about as likely to file for bankruptcy as other people the same age. Each year, about 1.1 percent of the former NFL players opted for bankruptcy -- just about the same rate at which the rest of the population of that age file for bankruptcy. 
 
 Economic models have long been based on the notion that people act rationally, and that a person anticipating an income reduction in retirement will dutifully seek to save money. But this research suggests just how difficult it can be for people to do that, said Camerer, a professor of behavioral finance and economic at the California Institute of Technology. 
 
 "We've known that it can be very difficult for the average family to save," Camerer said. "But this is one group that you might think ought to be able to avoid bankruptcy. They're in a position to buy some good advice if they need it. But even for them, with all these millions, it's a challenge." ||||| Rich Schultz/GettyImages Rob Gronkowski has made a little over $16.3 million in five seasons playing for the New England Patriots — and has saved all of it. 
 
 Peter King of theMMQB.com posted some excerpts from Gronkowski's coming autobiography, "It's Good to be Gronk." Among those excerpts was this tidbit on Gronk's thriftiness: 
 
 To this day, I still haven't touched one dime of my signing bonus or NFL contract money. I live off my marketing money and haven't blown it on any big-money expensive cars, expensive jewelry or tattoos and still wear my favorite pair of jeans from high school. 
 
 By star athlete standards, Gronkowski did not make much money when he first entered the NFL as a second-round draft pick. His first contract included a $1.8 million signing bonus, and his salaries during his first two seasons were $320,000 and $450,000, respectively, according to Spotrac.com. 
 
 But that changed after his second season in the league when he signed a six-year, $54 million contract with an $8 million signing bonus, and yet it sounds as if Gronk is still living like an underpaid rookie. 
 
 Gronk's endorsement deals have included BodyArmor SuperDrink and Dunkin' Donuts. ||||| On the morning of Oct. 7, two days before the Blue Jackets opened the 2014-15 season, Jack Johnson left his Ferrari parked in the garage of his Dublin apartment and drove his BMW to a federal courthouse Downtown to file for bankruptcy. 
 
 Johnson has earned more than $18 million during his nine-year NHL career, not including the $5 million he will be paid this season by the Blue Jackets. 
 
 Almost all of the money is gone, and some of his future earnings have already been promised — which is why Johnson, surrounded by a new team of financial advisers and an attorney, signed his financial surrender. 
 
 The scene was nearly four years in the making, after a string of risky loans at high interest rates; defaults on those loans, resulting in huge fees and even higher interest rates; and three lawsuits against Johnson, two of which have been settled and one that’s pending. 
 
 “I’d say I picked the wrong people who led me down the wrong path,” Johnson, a 27-year-old defenseman, told The Dispatch last week. “I’ve got people in place who are going to fix everything now. It’s something I should have done a long time ago.” 
 
 He has declined to comment further. 
 
 >> Around NHL, Jack Johnson’s bankruptcy a warning 
 
 >> Video: Dispatch reporter Aaron Portzline talks about Johnson's financial woes 
 
 >> Michael Arace commentary: Jack Johnson in sadly familiar predicament 
 
 >> See a slide show of Jack Johnson's career 
 
 >> What people on social media are saying about Jack Johnson 
 
 But sources close to Johnson have told The Dispatch that his own parents — Jack Sr. and Tina Johnson — are among the “wrong people” who led him astray financially. 
 
 In 2008, Johnson parted ways with agent Pat Brisson, who represents some of the National Hockey League’s biggest stars, including Sidney Crosby, Patrick Kane and Jonathan Toews. 
 
 With no agent and little knowledge of how the financial world works, Johnson turned over control of his money to his parents. 
 
 In 2011, in the weeks leading up to Johnson’s first big contract — a seven-year, $30.5 million deal signed with the Los Angeles Kings, under which he now plays for the Blue Jackets — Johnson signed a power of attorney that granted his mother full control of his finances. 
 
 Tina Johnson borrowed at least $15 million in her son’s name against his future earnings, sources told The Dispatch, taking out a series of high-interest loans — perhaps as many as 18 — from nonconventional lenders that resulted in a series of defaults. 
 
 The tangled web is one that The Dispatch has been investigating since the spring, and — according to court documents, NHL sources and sources with knowledge of the situation — involves a U.S. congressman from Iowa, the son of an oil baron in Texas and a former University of Michigan basketball star. 
 
 Because Johnson’s name is on the loans, he has been sued at least three times for more than $6 million for defaulting, as in the case of the mortgage on a house in Manhattan Beach, Calif. In court documents, Johnson says his parents bought the house with his money but without his knowledge. 
 
 Johnson’s parents allegedly each bought a car, spent more than $800,000 on upgrades to the Manhattan Beach property and traveled, often to see him play NHL games for the Kings and Blue Jackets. 
 
 “Jack would ask (his parents) questions: ‘What’s this? What are these guys calling about?’ ” a source said. “And they would tell him not to worry about it, just worry about playing hockey. 
 
 “These were his parents, right? He trusted them. It wasn’t until last spring or early summer that he understood there was a significant problem.” 
 
 In his bankruptcy filing, Johnson claims assets of “less than $50,000” and debts of “more than $10 million,” although sources say the debt could be in the neighborhood of $15 million. 
 
 A bankruptcy hearing is scheduled for Jan. 23 in Los Angeles. 
 
 Tina Johnson’s cellphone number listed in court documents is no longer in service. Jack Johnson Sr. has not returned several messages left on his cellphone, and several of the lenders have no storefronts or business phones. 
 
 Johnson has cut off all contact with his family, a source said. 
 
 Johnson’s paychecks from the Blue Jackets have been garnisheed to the point where, at the end of last season, “His paychecks were gone before he even got them,” a source said. 
 
 “I’ve seen lots of instances of parents riding their kid’s coattails around,” said an NHL executive familiar with the case. “I’ve never seen a case as ugly as this one, where the parents took such advantage of their kid.” 
 
 Retracing the problems 
 
 Johnson has been a big deal in hockey circles since he was a teenager. 
 
 He attended Shattuck St. Mary’s School, an elite boarding school in Minnesota, where he became close friends with teammate Crosby, now an NHL superstar with the Pittsburgh Penguins. 
 
 To stay close to their son, Johnson’s parents rented a home one block from the school. 
 
 When Johnson went on to play two seasons at the University of Michigan (2005-07), his parents were omnipresent there, too. Jack Sr., who played hockey at the University of Wisconsin, was a hit with Wolverines fans for his second-intermission dances during home games in Ann Arbor’s Yost Ice Arena. 
 
 And it was at Michigan, sources say, that Johnson’s path to financial ruin began. 
 
 Maurice Taylor, a star basketball player at Michigan from 1994 to ’97 who was later disassociated by the school after a string of NCAA violations, steered Johnson and his family toward Simon Vo, who was to serve as Johnson’s business manager after Johnson fired Brisson, the agent. 
 
 Johnson had been paid relatively modest salaries early in his career, earning a high of $1.6 million in his fourth season in the league. 
 
 In the months leading up to his $30.5 million deal with the Kings, however, Vo and Steve Miller, who owned a mortgage company in Los Angeles, began discussing with Johnson’s parents the idea of “monetizing” Johnson’s contract, sources said. 
 
 “Monetizing” — that is, borrowing against guaranteed future salaries — has led to the financial woes of many professional athletes. 
 
 One prominent NHL agent, asked whether he would ever advise his clients to monetize a contract, responded: “Never, never, never.” 
 
 Two months after Johnson’s big contract extension was signed with the Kings on Jan. 8, 2011, his parents began borrowing money against their son’s earnings, court documents show. 
 
 Things quickly got out of control. 
 
 “Intended or unintended, there are cases where there is a sense of entitlement among the parents of pro athletes,” said Gary Marcinick, a partner at Columbus-based Budros Ruhlin & Roe, a fee-only wealth-management firm. “It’s more common than you think. 
 
 “The families have made great sacrifices to get these players where they are. That’s the thought process. It’s almost a tribal sense — that they’re all in this together.” 
 
 Marcinick — who has worked with several pro athletes, including several current and former Blue Jackets players — said he has no knowledge of Johnson’s situation and would not discuss it specifically. 
 
 But, he said, the idea of a player being unaware that he is millions of dollars in debt is both hard to fathom and entirely believable. 
 
 “It is plausible; I’ve seen it,” Marcinick said. “These players are so young, and they have a lot of money coming in — so they’re targets. They rely blindly, often, on the judgment of their parents or agents, and they sometimes have agendas that are not optimal. 
 
 “Players find it difficult to question their agents. They don’t even know the right questions to ask. And they’re even more reluctant to question Mom and Dad.” 
 
 Miller was the first lender, extending a $1.56 million loan on March 9, 2011, that Johnson’s parents used to buy the home in Manhattan Beach, a third of a mile from their son’s residence, while he played for the Kings. 
 
 Johnson, a source said, believed that his parents took out a mortgage using money left to them in the will of a relative who had recently died. 
 
 The loan — which carried a 12 percent interest rate, almost three times the market rate — quickly went into default because it called for an initial payment of more than $1 million. (The contract extension Johnson signed with the Kings didn’t kick in until the following season, and he didn’t have that much in the bank.) 
 
 One day after the home loan was signed, on March 10, 2011, the Johnsons borrowed $2 million at an interest rate of 12 percent from a software developer in Iowa named Rodney L. Blum, who this month won a seat in the U.S. House. 
 
 Blum’s office did not respond to interview requests left with Blum’s spokesman by The Dispatch. It’s unclear how Johnson’s family came to know him or why he was making a personal loan at a high interest rate. 
 
 Barely a month later, on April 14, 2011, the Johnsons borrowed $3 million — at 24 percent — from Pro Player Funding in upstate New York, a company that “monetized” several NFL players’ contracts during a work stoppage. Former NFL stars Vince Young, who went bankrupt, and Bryant McKinnie, who was sued for default, were among the company’s clients. 
 
 Johnson was sued by both Blum and Pro Player Funding within a month of the loans being signed. He signed settlements, according to court documents, without appearing in court to contest the lawsuits. 
 
 To settle Blum’s suit, Johnson had $41,800 — or 25 percent — garnisheed from his bimonthly Blue Jackets paychecks over much of the past two seasons. 
 
 The next two years brought additional loans and additional defaults, sources said, but the next loan that ended up in the court system was extended on Sept. 13, 2013: a $400,000 loan at 18 percent from EOT Advisors in Tarrant County, Texas. 
 
 Adam Blum, son of an oil baron and operator of EOT Advisors and other financial planning firms, would not comment through his attorney. Blum is not believed to be related to Rodney Blum. 
 
 EOT Advisors sued Johnson on Dec. 30, 2013, for $1 million and for fraud, saying the loan application failed to disclose his true financial standing. 
 
 The case remains open, although it is frozen because of Johnson's bankruptcy filing. 
 
 Digging out 
 
 Johnson will find it easier, those close to him say, to make financial restitution than to reopen his relationship with his parents. 
 
 Those close to him say Johnson is pretty frugal. The Ferrari, which likely will be a casualty of the bankruptcy, was the one “extravagant” gift he bought for himself upon turning pro, a source said. 
 
 When Johnson demanded transparency from his parents and hired his own attorneys and financial advisers in May, he took aim at the first loan taken out in his name. 
 
 On Sept. 22, he sued Miller, National Mortgage Resources and Vo and his company, CYA Investments, for at least $1.5 million, including punitive damages. 
 
 Johnson’s suit was intended in part to stop Miller and National from foreclosing on the house in Manhattan Beach, where his parents lived until he unearthed his financial woes. 
 
 Johnson had a buyer ready to pay $1.8 million for the home — money he would have used to pay the debts remaining from the initial loan, he said. 
 
 But the courts denied Johnson’s injunction to prevent the foreclosure. 
 
 In the court filing, Johnson describes the loan as “egregious, unethical and wrongful,” and said it was a “deliberate and predatory lending scheme ... to line their own pockets at the expense of Johnson.” 
 
 Further, the filing says, they “unscrupulously” conspired to have Johnson’s mother acquire the power of attorney, and that he was “provided only the ‘signature page’ of the loan document and requested, by his mother, to sign.” 
 
 Two sources close to Johnson say he is confused and hurt and is concerned about the well-being of his 16-year-old brother, who lives with his parents in Michigan. 
 
 But Johnson, sources told The Dispatch, doesn’t want to pursue criminal charges against his parents, who aren’t named in his suit. 
 
 John Davidson, the Blue Jackets’ president of hockey operations, would not comment publicly but did say the club is aware of Johnson’s situation and is “standing beside him.” 
 
 The NHL would not comment on Johnson’s situation. The NHL players’ association certifies players’ agents but has opted not to certify financial planners, according to a spokesman. 
 
 Johnson’s Columbus-based attorney, Marc Kessler, said Johnson has surrounded himself with a network of people who, finally, are serving his best interests. 
 
 “Jack’s financial situation was detrimentally affected by the actions of those who were trusted to handle his business affairs,” Kessler told The Dispatch. “Unfortunately, these were predatory lenders going so far as to use Jack’s NHL contract as collateral. 
 
 “In order to best protect his future, he’s filed for Chapter 11 bankruptcy protection and he’s enlisted a new group of professionals who are helping him get through these matters. Jack remains focused on hockey. He appreciates the support of the entire Blue Jackets organization and the fans during what is a pretty difficult time.” 
 
 aportzline@dispatch.com 
 
 @aportzline ||||| The National Football League and New England Patriots will fight hard to get the Aaron Hernandez estate’s concussion lawsuit dismissed, but they could have an incentive to settle if that strategy fails, according to legal experts. 
 
 “The NFL will fight tooth and nail to get this case thrown out of court,” said Daniel Wallach, a prominent sports law attorney based in Florida, said Friday by phone. 
 
 His comments came one day after lawyers for Hernandez’s estate filed a $20 million lawsuit against the league and the Patriots, on the grounds that both parties failed to protect Hernandez from the effects of chronic traumatic encephalopathy, or CTE, a brain condition linked to concussions and repeated blows to the head. 
 
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 Wallach, who has advised top athletes and pro franchises, said the league probably will cite a number of factors in its bid to get the suit tossed, including the exclusion of any players who retired on or after July 2014 from signing onto a prior class-action concussion settlement expected to top $1 billion. 
 
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 Hernandez was in jail awaiting his first murder trial in July 2014, and the league could argue he fell into the retired player category because he had “no reasonable expectation” of resuming his playing career, Wallach said. 
 
 In addition, he said, the league will cite the full scope of Hernandez’s football career going back to his youth Pop Warner days, as well as his violent tendencies that predated his selection by the Patriots in the 2010 draft. 
 
 The team released the once-promising tight end immediately after his June 2013 arrest for murder. 
 
 Michael McCann, an attorney and founding director of the Sports and Entertainment Law Institute at the University of New Hampshire School of Law, agreed that Hernandez’s estate faces challenges. 
 
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 “These are difficult cases to bring, that a finding of CTE proves liability against the NFL,” he said. 
 
 At the same time, McCann added, the league might be tempted to settle if it can’t get the case dismissed, to avoid turning over documents in a protracted legal battle. 
 
 “It’s still a potentially threatening lawsuit to the Patriots and the NFL,” said McCann, who is also a leading expert on the Deflategate saga. “We know the Patriots are known to be private about various issues.” 
 
 So is the league, Wallach said. 
 
 “Five years into this overall concussion litigation, one thing the league has been very successful at is keeping its executives off the witness stand, avoiding testimony under oath, and not having any of its so-called treasure trove of documents in the public eye,” Wallach said. 
 
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 But a third expert, Andrew Brandt, said he doesn’t see a settlement on the horizon. 
 
 “My sense is they would not settle, as they would have a lot of defenses around Hernandez’s lifestyle and his short career in the NFL compared to other levels of football,” said Brandt, who heads the Moorad Center for the Study of Sports Law at Villanova University. 
 
 Hernandez was acquitted in April on charges of killing Safiro Furtado and Daniel de Abreu in a drive-by shooting in Boston in 2012. Five days after the acquittal, the 27-year-old Hernandez hanged himself in his prison cell at Souza-Baranowski Correctional Center. 
 
 He was serving a life sentence for the June 2013 killing of Odin L. Lloyd. A judge later vacated Hernandez’s first-degree murder conviction in the Lloyd case because Hernandez had not exhausted his appeals at the time of his suicide. Bristol County prosecutors are challenging that decision. 
 
 The league, citing Hernandez’s criminal history, vowed Friday to vigorously defend itself against the lawsuit. 
 
 Material from The New York Times was included in this report. Ben Volin and Milton J. Valencia of the Globe Staff contributed to this report.
– Sean Avery could take a page from Rob Gronkowski's book—literally. Gronkowski of the New England Patriots has raked in more than $16.3 million in signing bonuses and contract money over five seasons in the NFL and, incredibly, hasn't spent a penny of it, according to an excerpt from his autobiography It's Good to be Gronk, per theMMQB.com. "I live off my marketing money and haven't blown it on any big-money expensive cars, expensive jewelry, or tattoos and still wear my favorite pair of jeans from high school," the tight end explains. Gronkowski, who started out making $320,000 and $450,000 in his first two seasons, respectively, has counted BodyArmor SuperDrink, and Dunkin' Donuts among his endorsers, reports Business Insider. Gronkowski stuck to his financial plan after signing a six-year, $54 million contact with an $8 million signing bonus, but that isn't possible for everyone. In fact, one in six NFL players will file for bankruptcy within 12 years of leaving the league, according to a study published earlier this year, per the Washington Post. About 2% of players filed for bankruptcy two years after retirement, despite making an average of $3.2 million over their careers. "This is one group that you might think ought to be able to avoid bankruptcy. They're in a position to buy some good advice if they need it," a financial expert said. "But even for them, with all these millions, it's a challenge." The report found NFL players file for bankruptcy at about the same rate as non-athletes of the same age.