Four weeks is "best case scenario" for Fred Jackson's return
This really shouldn't concern the Bills all that much. Fortunately for them, they have electrifying runner CJ Spiller "backing up" Jackson, though they likely would have shared touches almost evenly. Spiller racked up 194 total yards on Sunday, and made several jaw dropping plays along the way to keep his team from being completely embarrassed in the Meadowlands.
Though this is no time to panic for the Bills, it may be time to panic for fantasy owners. This is why you spend those boring mid- to late-round picks on handcuffing your running backs. If you got Jackson early, I sure hope you got Spiller later. If you did, you might be better off with Spiller as the workhorse than you were with Jackson sharing touches. If you stole Spiller from Fred Jackson's owner, good for you - you've got yourself a stud for the next month, or maybe even longer.
Spiller averaged 12.1 yards per carry on Sunday. While there's obviously no chance he could maintain that for the rest of the year, he did average an impressive 5.2 yards per carry after Fred Jackson broke his leg last season, so Spiller has proven that he can be effective as the Bills' featured runner.