Jets" Sanchez, Used to Stability, May Soon Confront Uncertainty FLORHAM PARK, N.J. - Mark Sanchez transferred to Mission Viejo High School before his junior year, and his football career has been a portrait of stability ever since. He played for one head coach at Southern California, where he worked with the same offensive mentor for four years, then joined the Jets just as a new staff was taking over. Unless the Jets overcome long odds Sunday to make the playoffs, Sanchez could be forced to confront an uncomfortable and unfamiliar reality. Based on their reactions the last three times they failed to qualify for the postseason, the Jets would seem poised to make a significant change, and any reckoning would appear to include the maligned offensive coordinator Brian Schottenheimer. As much a friend as his coach, Schottenheimer could be the first mentor to leave Sanchez since Steve Sarkisian, his quarterback tutor at U.S.C., took the head coaching job at the University of Washington in 2008. "We all missed Sark," said Jets receiver Patrick Turner, a college teammate of Sanchez's, "but he was really Mark's guy." Sanchez was shocked by Sarkisian's decision, but he was also on his way out, declaring a month later for the N.F.L. draft. His prospects are no less uncertain, and they might not be as bright either. The potential upheaval surrounding the team is simmering just as the perception of Sanchez, 25, has started to shift, as it has become clearer that he has not progressed as the Jets had hoped or expected in this, his third season, a critical one by N.F.L. quarterback standards. In his first two years, Sanchez delivered some memorably miserable performances, but the counterpoint was always that he won. Consecutive appearances in the A.F.C. championship game reinforced that reputation, as did his four postseason road victories, a feat matched by only Len Dawson, Jake Delhomme, Joe Flacco and Roger Staubach. That success highlighted some of his strengths, like his toughness and his durability, but the downside was that it masked certain deficiencies, some of which remain obscured by what are career bests this season in completion rate (56.2 percent), touchdowns (24) and quarterback rating (79.0). "There's a lot of things to like about the kid, but there's a lot of negatives, too," said the former quarterback Rich Gannon, now an analyst for CBS. The decision-making, the completion percentage, the accuracy, the ability to sit in the pocket and throw from the pocket. I've seen him too many times just this year alone where there's been some issues. Sanchez has grown so accustomed to the scrutiny that, to borrow one of Coach Rex Ryan's favorite phrases, by now he has skin like an armadillo. Never before, though, has he been forced to defend himself this much, and against criticism that transcends the week-to-week variety, cutting right to his long-term viability with the organization. Sanchez's oldest brother, Nick, recently said that Mark fully understood that pressure, particularly in a demanding city like New York, and accepted it "knowingly and willingly." "He knows what he expects from himself and what's expected of him," Nick Sanchez said. Sanchez's evolution is linked to Schottenheimer, a holdover from Eric Mangini's staff, with whom he formed an immediate bond after being drafted No. 5 over all in 2009. And among the 24 quarterbacks who have thrown at least 1,000 passes since then, Sanchez ranks 24th in completion percentage (55.1), quarterback rating (73.4) and passing yards per game (195.7), and 23rd in yards per attempt (6.5), according to Pro-Football-Reference.com. Part of the problem, at least this season, derives from the fact that the Jets no longer have the shutdown defense or dominant running game of years past, which puts more pressure on Sanchez to perform. The Jets are more likely to retool their offense than jettison Sanchez, and if Schottenheimer is indeed fired, one potential internal replacement is the offensive line coach Bill Callahan, who also coordinates the running game. Elevating Callahan might not constitute as much of a shake-up as fans would prefer, but continuity is an essential component in the development of a young quarterback like Sanchez. If an outsider came in with a vastly dissimilar offense, he could do more harm than good to Sanchez. Sanchez is certainly not on the level of Tom Brady, who was unaffected by New England's coordinator changes because the same system remained in place. Is it one guy adjusting to what the Jets want to do, or is it 35 guys adjusting to what the new guy wants? Gannon said. For me, it makes much more sense to hire somebody who speaks the same language, who has the same philosophical beliefs. For perspective, Sanchez can look within his locker room at Mark Brunell, who has played for 10 offensive coordinators. Or toward the other team in town, the Giants, whose backup, David Carr, encountered similar turbulence in Houston after his fourth season, when the new coach Gary Kubiak hired Troy Calhoun to direct the Texans" offense "I felt like I was a rookie again," Carr said, adding: "Not only do you have to learn it, but being an experienced guy, you realize you have to teach it as well. You realize you have to go out and exude some confidence to your teammates. Brunell was 24 when Green Bay traded him before the 1995 season to Jacksonville, where he bounced among five coordinators during his nine seasons. The turnover did not hurt him, he said, because all of them followed the downfield passing style favored by his coach at the time, Tom Coughlin. Brunell, now 41, said his arrival in Jacksonville was more difficult because he had to forget all of the terminology associated with the Packers" West Coast offense. "Part of that was because I was so young," Brunell said. I hadn't seen a lot. I hadn't been in a lot of systems, and that's why I didn't get comfortable until about halfway through that season. Sanchez hopes to have a career as long (19 seasons) and as productive as Brunell, who considers him an apt pupil. But this off-season, the Jets may consider adding a more credible backup, someone to push Sanchez. Just one more new relationship to build. Mark Viera contributed reporting.