Adrian Peterson starts camp on PUP list

Vikings RB Adrian Peterson (knee) has been placed on the PUP list to start training camp.  AP reportedly pushed management to allow him to practice, but the team is wisely playing it safe with their stud back.  While it's unclear how much work he'll get in during camp and preseason action, Peterson is still tentatively expected to be ready for Week 1.  RB Toby Gerhart is getting the 1st-team reps in his absence.