Wednesday, February 25, 2009

Rosenfels vs. Jackson

With Sage Rosenfels set to join the Vikings as soon as the trade can be consummated -- 12:01 Eastern, Friday morning, to be exact -- many fans are already predicting that he'll easily oust Tarvaris Jackson as the Vikings' quarterback. While that may yet happen, it shouldn't be the slam-dunk, no-questions-asked decision some think it ought to be.

Somewhat conveniently, both quarterbacks have career pass attempt totals that are about in line with a full season's worth of passes, albeit for a rather pass-happy team: 561 for Rosenfels and 524 for Jackson. This allows us to compare their stats, side-by-side, with no real manipulation needed and to consider how they'd look if they really were single-season stat lines.


I've italicized the better numbers for each quarterback. Yes, I realized Jackson's better rushing numbers come with more attempts, but I don't think anyone will dispute that Jackson's a better runner than Rosenfels.

In this rather simple comparison, the numbers come out in favor of Rosenfels, 6-3. He's racked up more yardage, at a better rate per attempt (7.4 to 6.6) than Jackson; even his yards per completion is slightly better (11.8 to 11.2), showing that that's not just the result of Jackson's mediocre completion percentage. While clearly not a better runner than Jackson, Rosenfels has nonetheless done a much better job of avoiding sacks, going down at about half the rate of Jackson and fumbling with less frequency.

But there are negatives to Rosenfel's superior numbers, the most glaring of which is his interception total. If this were a full season's stats, 29 interceptions would be practically unacceptable for a starting quarterback. I've not seem him play much, but it's possible that part of the reason for Rosenfels' lack of sacks comes from him throwing the ball away and into coverage, thus resulting in the very negative play (interception) instead of the somewhat negative play (sack).

In any case, for all that Vikings fans -- such as this one -- complain about Jackson's prediliction for turning the ball over, it's clear that Rosenfels is markedly worse at protecting the football. Assuming that 2/3 of each player's fumbles were recovered by the defense (the typical NFL rate), that would give Jackson about 10 lost fumbles to Rosenfels' 8 for their careers. That gives Jackson 28 turnovers and Rosenfels 37. That's a rate of 4.2% for Jackson (when dividing turnovers by attempts+sacks+rushes) and 5.9% for Rosenfels. Finally, we can look at the rate stats for each QB. Rosenfels clocks in with an 81.2 passer rating and 4.48 TYA. Jackson's a 76.5 and 4.13, so the slight edge there goes to Rosenfels.

Still, if there's anything the Vikings need at the quarterback position, it's someone who doesn't turn the ball over and gives the defense and running game a chance to win (i.e., more of a "game manager" than a "gunslinger"). Rosenfels, at least through the first part of his career, doesn't fit that mold. Perhaps, as a career backup, he's been trying to "force" plays to make himself look better and impress in his limited playing time (the "Rosencopter" again comes to mind). With Adrian Peterson to hand off to and a world-class defense backing him up, perhaps he won't feel the need to try and do so much in Minnesota. (Then again, he won't have Andre Johnson to throw to anymore.) And there's little doubt he's got a stronger arm and looks better in the pocket than Jackson.

But, as I've said before, looks aren't everything. Rosenfels is probably better than Jackson, but only marginally so, and if the turnovers come in bunches in 2009, Brad Childress will need to do whatever he can to save his job -- even if that means going back to the safer, more careful Tarvaris Jackson. And who ever thought that would be the case?

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