MANKATO, Minn. — The Minnesota Vikings have placed wide receiver Greg Childs on the physically unable to perform list to start training camp.

The first practice was Friday. Childs did conditioning drills off to the side under the supervision of an athletic trainer. Childs is recovering from torn patellar tendons in each knee, a gruesome injury suffered early in training camp last year, ending his rookie season before it began.

Linebacker Nathan Williams, an undrafted rookie from Ohio State, was also placed on the PUP list. He's recovering from ankle surgery. Unlike the PUP designation during the regular season, players on the PUP list during training camp count against the 90-man roster.

Center John Sullivan, who had microfracture knee surgery over the winter, is practicing with the team, with his repetitions limited.