People who say you can't measure football players with stats often mention that football games aren't played on paper. It's true, but what good statistics do is take context-irrelevant metrics like yards and actually apply them to winning games.
That leads to our rhetorical question of the week: How can you run for 111 yards and have the second-worst performance of any running back in Week 6? The answer is to have a day like Adrian Peterson's on Sunday, where the yardage you rack up has little to do with your team actually pulling out the win. When your margin of victory over the hapless Lions is an inscrutable Dan Orlovsky safety, it's a sign you've done something wrong. If we break down Peterson's performance, we can see how little his rushing yards had to do with success.
Let's start with the positive: Peterson gained those 111 yards on 25 carries. That's an average of 4.44 yards per carry, which is good in a vacuum. Now, let's take some air out of those figures by looking at the context in which they were gained. First, Peterson fumbled twice. His first fumble came on a third-and-1 at the Lions' 11-yard line, turning a likely minimum of three points into zero. His second fumble took place on the Lions' 43, much further away from the goal line, but it was in the fourth quarter with Minnesota down a point.
Now, let's address the other factors. Peterson had two third-down chances; he converted neither, ending both drives. He moved the chains only four times in 25 carries. Peterson had six carries on first down of 3 yards or less, putting the Vikings in second-and-long far too frequently. In the passing game, Peterson contributed nothing, with one incompletion and a screen pass that lost 5 yards.
Finally, you have to consider the opposition when judging performance. Peterson was playing the Detroit Lions, a team that redefines embarrassment on a weekly basis. (When is the last time you saw a quarterback forget the size of the end zone?) Going into Week 6, the Lions had the worst rush defense in the league, according to our advanced DVOA stats, giving up huge chunks of yardage when it mattered and eventually bunkering down when no one cared about the outcome late in games.
Factoring all these variables in, Peterson's 111-yard rushing day amounts to an ugly -45 DYAR, the second-worst performance of the day. There's no doubting Purple Jesus' talent, but on Sunday, his raw yardage only told a fraction of the story.
Here are the rest of the best and worst players of Week 6, according to the Football Outsiders DYAR (Defense-adjusted Yards Above Replacement) statistics. Note that with six weeks played, opponent adjustments are currently at 60 percent strength.
Bill Barnwell is an analyst for FootballOutsiders.com.