"Six weeks ago, Matt Cassel was the Chiefs' weak link. He was the problem. He was the reason the Chiefs weren't yet seen as a legitimate playoff contender.

That was the talk, anyway.

Now, he's a major reason the team has a two-game division lead on San Diego and Oakland. He is proof of progress and growth. He is the ideal quarterback for what the Chiefs want to do.

Coach Todd Haley said this week, a day after Cassel's ninth game this season without an interception, that he would prefer a quarterback who limits mistakes — rather than a gunslinger who might average 350 passing yards per game and turn ordinary receivers into Pro Bowlers.

Cassel is 18th in the league with 2,503 yards passing. Hardly an inspiring number. But he has thrown only four interceptions, or one every 88.5 pass attempts. Cassel is tied with New England's Tom Brady with the second-fewest interceptions. Only Philadelphia's Michael Vick, who has attempted 86 fewer passes than Cassel, has thrown fewer interceptions, with two.

Haley said this week he wouldn't change a thing about his quarterback.

"Statistics mean nothing to me," Haley said. "It's about winning games, and that's proven. You can go through years and years of passing yardage, and you just can't find a correlation between that and winning and losing, where in turnovers you can."

This hasn't been a memorable season for many big-name quarterbacks. Peyton Manning has 15 interceptions. Drew Brees has 16, and Philip Rivers has 10. Vick, who before this season hadn't been a starter since 2006, is leading most MVP discussions. And Cassel has emerged as one of the NFL's most efficient quarterbacks. So it has been an unusual kind of year.

From the start, Haley has said that his quarterback's good days will be determined by how he protects the football. A good passer in this system is one who limits turnovers. An unacceptable performance takes the ball out of the offense's hands, and for this coach and this team, it really is as simple as that.

And although, by those standards, Cassel has had only three bad games this season, Haley remembers the mistakes well."