Adrian Peterson has vowed to be on the field for the Vikings by Week 1 of the regular season and that goal appears to be closer than initially thought. Minnesota could activate the running back as soon as Sunday from the physically unable to perform list. Peterson has worked his way back after tearing anterior cruciate and medial collateral ligaments in his left knee. "We're going to discuss it," coach Leslie Frazier said of activating Peterson. "We'll discuss where he is and what's the next step for him this week, whether we continue to work through rehab or how we want to approach it."