The Jaguars' costly QB mistake

Luke McCown had a disastrous game against the New York Jets. Jeff Zelevansky/Getty Images

We've seen a couple of genuinely horrible performances by quarterbacks in the first two weeks of this NFL season: Kerry Collins' horror show in Week 1 (Total QBR: 2.3) -- which we had some fun dissecting here -- and then Luke McCown's stink bomb on Sunday (Total QBR: 0.4), which was historically awful. But there's a difference: The Colts' situation was forced, whereas Jacksonville's was technically voluntary. The Jaguars cut David Garrard just before the season started, and chose to hand the reins to McCown.

McCown's raw numbers on Sunday were terrible: a completion rate of just 32 percent, only 59 passing yards, four interceptions and no touchdowns. Indeed, he became just the fifth QB in the past 15 years to pull a Burris -- the Next Level term for throwing four or more INTs in fewer than 20 attempts. (The Burris is named for Bears backup QB Henry Burris, who accomplished this feat in a 15-0 loss to Tampa Bay in 2002.) But if you look at McCown in the context of game situations, his performance was even worse. He took a sack in the end zone with the Jaguars down by seven points, threw two interceptions while they were within nine points and just three of his 19 pass attempts went for first downs. In all, McCown posted the third-worst QBR for any quarterback with at least 20 plays in any single game since 2008. (The worst? I've dropped enough hints in my pieces on QBR for you to guess. Be the first to get it right, and you'll win a prize.)

OK, so McCown was bad. But what's more important is to find out what it all means; we have to quantify just how much Jacksonville's quarterback shuffle -- which now involves starting rookie Blaine Gabbert -- is costing the team.

From 2008 through 2010, Garrard was almost exactly in the middle of the pack of NFL starters, ranking 16th in the league with a QBR of 52.5. He added 126.5 expected points to Jacksonville's offense over that span, or 6.3 points per 100 plays. Given that starting QBs average about 35 plays per game, or 557 plays per full season, the difference between Garrard's established level of performance and what the Jags should have expected of McCown is a whopping 5.6 points per game, or 90 points a year.