The greatest hypothetical question for the just-completed Vikings season is, of course, what would have happened to this 7-9 squad had Adrian Peterson played the entire season instead of missing 15 of 16 games as a consequence of his legal problems?
Like all hypothetical questions, it's impossible to know the answer (unless you have a key to an alternate universe that would play out the 2014 Vikings season with AP in the mix. If you do, please don't use it on football. Use it on something cool like a version of The Matrix in which Tom Cruise really does get the role of Neo).
In the mean time, all we can do is make an educated guess. And here are three things we think would have happened:
1) First, clearly, it would have benefited the Vikings. We probably don't need a hypothetical answer to know that. But how much would it have benefited the Vikings?
We've heard it suggested that the Vikings might have challenged for the playoffs with Peterson on the roster all year, and that is almost certainly not true. There were too many other holes on this team, and there is also the relative contribution of running backs to victories.
The site Advanced Football Analytics attempts to put a value on players called "Win Probability Added," which is similar to baseball's "Wins Above Replacement." It's an imperfect stat, but it at least gives us a baseline for a conversation.
In the course of his career, Peterson's cumulative WPA is 4.15. Yes, just a little more than four wins for his entire career. Even in his best season, Peterson's WPA was 1.24 (2012, his MVP year). Matt Asiata this year had a WPA of 0.45, good for 14th in the league. So based on raw numbers, even if Peterson had his best season ever, the difference between Peterson and Asiata would have been good enough for fewer than one win. (A really good quarterback can have a WPA for a single season above 5, as Aaron Rodgers did this year. Teddy Bridgewater's WPA was 1.33 this season, 21st in the NFL and still better than Peterson's MVP year — underscoring how much more QB play matters than running back play).
Again, this is an imperfect metric. It's hard to account for just how much Peterson changes a defense's focus and how he might have helped in both the running and passing games. But the best guess is maybe the Vikings would have finished 8-8 with Peterson. Maybe 9-7 in an extraordinary case. And quite possibly they would have finished 7-9, just as they did.
