For NFL quarterbacks, time to put it up or shut up At some point soon, we'll have the answers to all the burning questions and lack of clarity surrounding the league's marquee position. The regular season starts this week, meaning the speculation has to end, right? For instance, we'll know if the New York Jets job truly belongs to shaky rookie Geno Smith or embattled veteran Mark Sanchez. We'll know whether the Oakland Raiders are putting their fortunes in the hands of Matt Flynn or Terrelle Pryor, both of whom have looked like not-ready-for-prime-time players. Are the beat-up Buffalo Bills actually opening with undrafted rookie Jeff Tuel at quarterback, or will first-round pick EJ Manuel, fresh off a procedure on his knee, rush onto the stage at the last minute? Appropriately, with NFL quarterbacks this season, everything is up in the air. In Washington, Robert Griffin III has been medically cleared to play in the opener against Philadelphia - his rebuilt knee passing the required tests, although he didn't take a snap during the exhibition season - but his doctor told the Redskins he still has concerns. Michael Vick is the starter in Philadelphia, having won the job over Nick Foles and rookie Matt Barkley. New Eagles Coach Chip Kelly is banking on Vick hanging onto the job better than he gripped the football the last two seasons - 24 interceptions and 21 fumbles in 23 games. One of the league's biggest mysteries this season is what type of offense Kelly will unveil. Vick, whose 5,551 yards rushing are the most by any quarterback in league history, sounds ready to return to his tuck-it-and-take-off ways, this summer blaming reporters for pressuring him to become more of a pocket passer. "You all did that to me," he said to a gathering of media. Made me change the way I played the game. So many questions, so little time. There's the fragile peace in Pittsburgh between swaggering quarterback Ben Roethlisberger and combustible offensive coordinator Todd Haley. They had a frosty relationship last season after Haley came in to replace the fired Bruce Arians, Roethlisberger's longtime coach and buddy. Haley felt far better this off-season and summer about his working relationship with Roethlisberger. "The quarterback wanted me to prove my worth last year," he said. He wasn't going to make it easy, which I understand. He was comfortable [with Arians], he didn't want to change, and he was made to change. But I was proud of myself. I didn't crack, didn't have any blowups. Could have. But now he tested me, and he's a different guy. Arians moved on, of course, winning coach-of-the-year honors in Indianapolis last season - the first interim coach to receive that award - after leading rookie Andrew Luck and the left-for-dead Colts to the playoffs. Now head coach in Arizona, Arians faces a new resurrection challenge. He's aiming to revive the career of quarterback Carson Palmer, who in his 11th season has played in only two postseason games, both with the Cincinnati Bengals. The Cardinals haven't been to the playoffs since quarterback Kurt Warner retired after the 2009 season, and it doesn't look good this year, not in the NFL's most competitive division, the NFC West. Like Palmer, San Diego's Philip Rivers is in a prove-it year, as is Chicago's Jay Cutler. All three are playing in new systems with new head coaches. What do we know about San Francisco's Colin Kaepernick? He's incredibly dynamic, both as a runner and a passer, and he helped get the 49ers to the Super Bowl, but he has started just 10 games. That picture is still coming into focus. There are questions surrounding two of the league's Canton-bound quarterbacks, Denver's Peyton Manning and New England's Tom Brady. With expectations for the Broncos as high as they've ever been, can Manning - rested after his first relaxing off-season in four years - assemble the type of spectacular season he had in 2012? As for Brady, the challenge is finding new ways to move the ball, without three of his go-to pass catchers from recent years. Receiver Wes Welker is now in Denver, tight end Rob Gronkowski is recovering from multiple surgeries, and tight end Aaron Hernandez is in jail on first-degree murder charges. A year ago, a record five rookie quarterbacks started openers. Griffin, Luck and Seattle's Russell Wilson all had exceptional seasons, while Miami's Ryan Tannehill and Cleveland's Brandon Weeden flickered with promise. With all those players heading into their second season, which ones will slog through a sophomore slump? Last season's sophomores, meanwhile, are heading into pivotal third seasons, and the pressure is on three 2011 first-round picks to step up or step aside - Minnesota's Christian Ponder, Jacksonville's Blaine Gabbert and Tennessee's Jake Locker. Quarterbacks who look lousy early in their careers can occasionally find success. Alex Smith did that in San Francisco, where he seemingly switched offensive systems once every three weeks. He was among the league's leading passers when he suffered a concussion last season and wound up losing his job to Kaepernick. Now, Smith and Coach Andy Reid are in Kansas City, both looking to reboot their careers and revive a proud franchise. But, beyond the money, being a first-round quarterback doesn't guarantee much. On a related note, after a weekend of final roster cutdowns, Matt Leinart, Vince Young and Tim Tebow are currently looking for work. Twitter: @LATimesfarmer