Quirks of the Game: The Roster Challenge When a baseball team loses a player to a midseason injury it fills that roster spot by calling up someone from the minor leagues, someone who has been playing regularly and coached by someone in the organization. But for N.F.L. teams the replacement is someone from the practice squad, who has probably not played a game all year, or someone sitting on his couch at home hoping for such a phone call. "The depth situation is one of the biggest challenges for teams," the Fox analyst and former Dallas fullback Daryl Johnston said. And with new rules about concussions it will be even more so going forward. Last week, after losing Andre Brown to injury, the Giants gave workouts to several running backs and then signed Ryan Torain and Kregg Lumpkin; Torain was playing in a seven-on-seven league in Arizona, and Lumpkin was applying for corporate jobs in Georgia. This week Green Bay brought back its former running back Ryan Grant, who had been home in New York working out and reading Malcolm Gladwell as he waited for an opportunity, while Detroit's wide receivers shortage led the Lions to promote Kris Durham from the practice squad and sign Lance Long, who played well in the preseason but failed to make the roster and who had been working out in Macomb, Mich. Coaches, even when desperate, are reluctant to give major responsibilities to someone just off the street, or even to practice squad players. There are exceptions of course. Last year linebacker Chase Blackburn, a former Giant, spent most of the season at home waiting for a chance. Detroit, Cincinnati and St. Louis worked him out during the season, but he was about to take a middle school teaching job when the Giants were decimated by injuries. Suddenly he was back in uniform making key interceptions against Green Bay and, in the Super Bowl, against New England. But Blackburn had played with New York since 2005 and had been let go largely for budgetary reasons. General managers have deep lists of who is available and give players workouts throughout the season. Still, for a billion-dollar entity like the N.F.L. it seems a bit of an ad hoc system, especially given concussion rules that will automatically mean more players temporarily sidelined. The league has always adapted to changing times, so the question now is whether there is a better way. "There are ways to improve the system but the issue is finding one that's practical," said the former Pittsburgh Steelers coach Bill Cowher, a CBS Sports "N.F.L. Today" analyst. The first order of business, he said, is expanding roster size. Michael Signora, the N.F.L.'s vice president for football communications, said the competition committee was open to considering such changes, something the league has done before. In the earliest days, teams had tiny rosters and players, fearful of losing their jobs, played through nearly any injury. In 1925 team rosters consisted of 16 players. They expanded the next year and to 20 four years after that. By the end of the 1930s, roster size had grown to 30 players, although even the biggest stars like quarterback Sammy Baugh still played offense and defense. Roster size gradually grew until 1964, when it reached 40 players. Since 1973, except for three years, it has never fallen below 45. Today, teams have up to 46 active and 53 players total - and they now can invite 90 players to camp instead of 80 - but finding enough time for everyone in practice is impossible. "In training camp you can add more players but there are not enough reps for everyone," Johnston said, adding that since most teams know the majority of the guys they're going to keep, "the expanded training camp roster doesn't really work." "The issue is how do you prepare players when you know you'll have guys getting hurt," said Josh McCown, Chicago's third-string quarterback. For the last two years, McCown has spent the early part of the season coaching high school football awaiting a call; both times, Jay Cutler has gotten hurt and McCown has gotten signed. Both years, his team lost in the playoffs the week before the Bears called. McCown, who has thrown for nearly 7,000 N.F.L. yards in 52 games, said that while he loved working with children, coaching also afforded him a chance to throw every day. But, he admitted, that is not nearly enough to get him ready. "You need to have players acclimated to the speed of the game," Cowher said. These players haven't taken a hit or made a tackle all year. Another possibility would be to expand the practice squad size, McCown said, allowing in veterans "who want to be around" (current rules for practice squad eligibility are extremely restrictive in terms of N.F.L. experience). But even the players on the practice squad do not get any time during the season to run through live practices with the first team. "That's harder on the young guys than the guys who have been in the fire before," McCown said. But even a bigger practice squad is not enough. Cowher and McCown, who in 2010 played in the United Football League, which has folded, said they thought the N.F.L. needed an affiliated minor league, something equivalent to Class AAA in baseball. "There are certainly enough guys interested, so you'd be able to field teams and have competitive football," he said. Not only are there enough veterans there to make it competitive and help keep them game-ready, Cowher said, "it could also help with developing young players." Of the proposals floating around, the most detailed and intriguing is Bleacher Report's Scott Carasik's idea of a 16-team league that even has the possibility of commercial success, à la minor league baseball. But that idea may be more ambitious than what the N.F.L. is willing to take on. In May, Commissioner Roger Goodell said the league was warming to the idea of a minor league but "my personal view is it should be defined what the actual objective is." He added: "If it is a developmental league, let's call it a developmental league; let's design it as a developmental league. If it is going to be a commercial league that is trying to generate fan interest or generate revenue, we should also be clear of that objective. I think our general view right now is to make it a developmental league. That would help teams and young players, but it would still leave players like McCown, Ryan Torain, Ryan Grant or Chase Blackburn sitting at home, waiting for the phone to ring.