Mark Sanchez and the Eagles had a very short week to prepare for Thursday's NFC East showdown with the Dallas Cowboys, but, in some ways, time is even shorter for the quarterback than for the rest of his teammates.

Sanchez faces a ticking clock as he makes his fourth start while Nick Foles recovers from a collarbone fracture. If he plays well enough, time can slow down a little and the organization might be less inclined to rush Foles back into the lineup. If he plays poorly, the hands of the clock will begin to spin around, and what might be Sanchez's last chance to redeem himself as an NFL starter could vanish.

It is a crucial moment in a career during which Sanchez himself has often been a ticking bomb, with only a matter of time separating him from a very bad outing. The question is whether his play has matured since his four seasons starting for the Jets or whether Chip Kelly's coaching has merely delayed the inevitable.

So far, Sanchez has been acceptable in his relief role. Not great, not terrible, but always with enough mistakes mixed in to cause concern. He has thrown six interceptions in 146 attempts, taken eight sacks, and has been inaccurate as often as he has been accurate.

Kelly has shrugged it off, reminding everyone that Sanchez missed all of last season with an injury and that not all of the mistakes have been his fault. The quarterback has been fine, according to the coach, and the miscues are fixable. Sanchez thinks so, too.

"There's a couple [of bad throws] that should have just been eliminated, period," Sanchez said of his up-and-down game against Tennessee. "Am I ever physically going to throw a bad ball again? Yeah, sure, at some point that will happen. That's the way it goes. You try to practice to eliminate those, but they happen. You have to diagnose it and move on."

The diagnosis is that every quarterback has passes he'd like to take back, but the prognosis in the case of Sanchez is that there will eventually be more of them than is acceptable. In all probability, Sanchez will remain the starting quarterback if he can play a little better than he has to this point. Bringing back Foles after six to eight weeks of inaction, and just before the start of the playoffs, would be risky. A case can be made for keeping Sanchez in there. But what if he suffers through one of those games? What then? Sanchez knows the answer and knows what is riding on a tough three-game stretch that begins at AT&T Stadium against the Cowboys.

"This is when you want to win, in November and December. Those games are big," Sanchez said. "I think we've put ourselves in good position to this point. Now we've got to take advantage of it."

This is his first "big" game with the Eagles, but he played in a few for the Jets. When he was successful with New York, it was for a team that had a dominating defense and a strong running game, and the quarterback wasn't always asked to do a lot.

In his rookie year, as the Jets made the playoffs by beating Indianapolis and Cincinnati in the final two games, Sanchez threw 19 and 16 passes, respectively, and had quarterback ratings of 78.0 and 60.2. The Colts rested Peyton Manning in the first game, and the Jets' defense shut out Cincinnati in the second.

The Jets then won two postseason games to make it to the AFC championship game. They beat Cincinnati with an offense of 15 passes and 41 rushes, then beat San Diego on a day the defense set up the go-ahead touchdown with an interception and Sanchez had a rating of 60.1.

In 2010, the Jets were 11-5 with Sanchez posting a season rating of 75.3, and they didn't have to fight through any big games at the end. In the playoffs, New York again won twice (again on the road) to get to the AFC title game. The Jets beat Indianapolis, 17-16, in a defensive struggle, then beat the Patriots, 28-21, in what was truly the game of Sanchez's career. He threw for three touchdowns, no interceptions, had a rating of 127.3, and only a nitpicker would point out that three of New York's four touchdown drives began in New England territory.

The Jets were 8-5 in 2011 and headed for the playoffs again before they lost their last three games to fall out of contention. Sanchez had ratings of 67.8, 54.2, and 65.5 in those games.

In 2012, the 6-10 Jets never had a big game to play. Sanchez was benched in favor of Greg McElroy in the second-to-last game of the season, but McElroy suffered a concussion and Sanchez played his final game for New York, another loss, to finish the year with 13 touchdowns, 18 interceptions, and an overall rating of 66.9.

It's not pretty, but that's the "big game" resumé of Mark Sanchez as he stares down at another one against the Cowboys with all that baggage behind him and Nick Foles beginning to peek over his shoulder as well.

There's no reason it can't turn out differently with the Eagles, or that Sanchez can't invent a future that helps erase his past. But time is moving quickly now, and history makes it very clear for whom the clock ticks.