Daunte Culpepper retired from the NFL five days ago, saying he was tired of begging for a shot at a quarterbacking job, even as a backup. If the first weekend of the regular season is any indication, some of the same people who wouldn't return Culpepper's calls might wind up begging him to come back.

Three quarterbacks didn't finish games they started Sunday, with the biggest and — according to early reports — most serious blow coming in New England, where Tom Brady's left knee buckled after being hit by Chiefs safety Bernard Pollard midway through the first quarter.

His opposite, Kansas City starter Brodie Croyle, lasted until the third, then left with a bruised shoulder after getting sacked. In Tennessee, Vince Young entered the game late in the fourth quarter to boos — he'd already been intercepted twice — and departed a few plays later with a sprained knee.

Their coaches wouldn't speculate how long each of the three QBs will be out, since they won't know much until MRI exams are conducted Monday. But this is a fact: Sixty-four different quarterbacks started games during the 2007 regular season, about a half-dozen more than the five-year average; while some played themselves out of the job, plenty lost theirs due to injury.

Either way, the number suggests most teams would be smarter than ever to plow most of their resources in the basics — defense and a running game — and divert some of the energy and resources devoted to finding that unusually talented, durable No. 1 to developing and keeping capable backups on hand. Only five quarterbacks in NFL history have put together streaks of longer than 100 consecutive regular-season starts.

The fact that three of them — Brett Favre (254 games), Peyton Manning (161) and Brady (111) — started Sunday might have general managers thinking it's easier to find one than it actually is. Despite league rules and all the blocking schemes devised to protect them, quarterbacks remain an endangered species in the modern NFL.

Matt Cassel stepped in for the reigning MVP and managed a comfortable-enough 17-10 win. The Patriots caught a break by drawing the punchless Chiefs at home, and also because Cassel took nearly all the snaps during the preseason, while Brady rehabbed an injured foot. But teammate Randy Moss, the receiving half of the NFL's most potent passing combo, said the team had better not rely on luck.

"It kind of hurts, to be honest with you," Moss said. "I know the show must go on, and hopefully Matt Cassel is ready to step in."

A poll on the Boston Globe's Web site a few hours after the game suggested Moss wasn't the only one hoping. Around midnight, Cassel topped the balloting as a replacement "should Brady be out for the long term" with 40 percent of the votes, followed by Culpepper with 29. Chris Simms, who was scheduled to visit New England on Monday, came in third with 13 percent, edging out "someone else" and soon-to-be-45-year-old Vinny Testaverde.

Another question asked voters who was more responsible for the Patriots' success, Brady or coach Bill Belichick. Perhaps remembering how Belichick turned to Brady in September 2001, after starter Drew Bledsoe went down with a devastating injury, the coach narrowly outpolled the star 52 to 49 percent. We'll find out.

Cassel, meanwhile, won't be the only one looking to take advantage of the opportunity. Suddenly, the AFC East looks less settled and one of the beneficiaries could be Favre, who proved again what a marvel he remains.

Favre completed a very workmanlike 15 of 22 passes for 194 yards and two touchdowns in the Jets' 20-14 win over Miami. It didn't hurt, either, that New York had shored up its offensive line in the offseason and that, limited as Favre's knowledge of the New York playbook was, he wound up facing a team that managed only one win last season.

"I've said this from Day 1. I know I made the right decision," Favre said afterward about the long-running, retirement-unretirement saga that took him from Green Bay to New York. "I enjoy these guys. There's no guarantees what's going to happen the rest of this year, but we're 1-0."

A moment later, Favre said he looked up at the scoreboard, saw the Vikings-Packers game scheduled for Monday night, and was surprised by his reaction. "I felt ... it wasn't like I was supposed to be there."

It's possible, though, that Favre could change his mind by season's end. The Packers and coach Mike McCarthy spent the past two seasons grooming Aaron Rodgers to replace Favre and — tired of being held hostage every offseason — finally told him to walk. But the Packers front office wasn't just planning a retirement party the past few years, instead retooling the defense and refurbishing the rushing attack so that whoever replaced Brett would have something to work with.

Rodgers won't probably put up numbers as good as Favre did during an MVP-caliber performance last season in Green Bay: 28 TD passes, 15 interceptions and a 95.7 quarterback rating. But as long as he's better than Favre's two previous seasons — 47 interceptions against 38 TDs — the Packers' chance to get deep into the postseason looks at least as good as the Jets'.

And if Rodgers gets hurt, well, Culpepper might still be available. Just last week, after months of trying to land a tryout without success, he named Green Bay as a place he'd be happy to relocate.

Here's hoping that McCarthy didn't lose his number.