Adrian Peterson could sit out beginning of camp

Vikings HC Leslie Frazier hinted that RB Adrian Peterson (knee) may be held out of the beginning of training camp next month.  "I don't know if we'll put him on the practice field anytime soon when we get to Mankato," Frazier said.  "But everything indicates there's a very good chance he may be ready for that Jacksonville game (to open the regular season on Sept. 9). We're still far enough out that you really can't say that right now."  Beat writer Judd Zulgad expects AP to open camp on the PUP list.  He'd be eligible to come off the list and join practice at any point before Week 1.  After a slew of rose-colored reports on Peterson the last couple months, the news has been more sobering lately.  That's not a surprise for a guy who suffered such a serious injury so late in the year.  Peterson still seems ahead of schedule, though, and he has a good chance to at least take the field for the season-opener.  We'll continue to stay on top of the situation.