The timetable for RB Adrian Peterson's knee injury is far from known now, but the early prognosis is that a return prior to Week One is far from assured. On the one hand, the Vikings want to play it safely, knowing they potentially have $100 million ($36 million guaranteed) invested in him. On the other hand, however, they also know he is the centerpiece of the franchise offensively and that his healthy (and, hopefully, quick) return to a team that otherwise lacks an offensive identity is essential. Peterson has a torn ACL and a damaged MCL in his knee, which usally means a nine-month recovery time. There is some hope, however. Players such as Cadillac Williams and Wes Welker have suffered similar injuries late in seasons the past few years and were able to return to action the next Week One, even though they later said they were not back to feeling themselves at full strength until the following season.