MANKATO - As the Vikings prepared for their first practice of training camp Monday, coach Leslie Frazier gathered his players at midfield, where they had a moment of silence to remember Korey Stringer.
It was 10 years ago Monday that Stringer, the Vikings right tackle, died as a result of complications from heat stroke that he suffered during a practice. Earlier in the day, tight end Jim Kleinsasser had spoken to teammates about Stringer. Kleinsasser, a second-round pick in 1999, is the last remaining Vikings player who was a teammate of Stringer's.
"It's good to talk to the guys who didn't know him and tell them what he was like as a player, as a person," Kleinsasser said. "I sat down with [Steve Hutchinson] last night and was telling him stories. Korey would have loved having him play on the line with him.
"We have Korey's locker [behind glass] back at Winter Park. So guys see that as well. Maybe me talking to them will make it mean a little more when they walk past it."
Frazier was an assistant with the Eagles when Stringer died, but he certainly was impacted by what happened.
"It's a hard day for everybody leading up to this day," Frazier said. "... Everyone misses him. I wish he could come out and watch us practice today, but in a way I feel like he was there today."
The Vikings painted Stringer's No. 77 on a practice field at Minnesota State Mankato.
Harvin feeling fine
Receiver Percy Harvin said his "health is great" and that he didn't have any setbacks during the offseason in terms of the migraine headaches that he has battled the first two years of his career.
"We're optimistic that it's all pretty much behind me," said Harvin, who missed much of 2010 training camp. "It worked out good this offseason and I'm ready to roll."
He said his doctors "did a lot of things" in terms of helping to keep the migraines away, but refused to go into any detail.
Herrera opens on PUP
Right guard Anthony Herrera, whose 2010 ended when he tore his left anterior cruciate ligament in November, started camp on the physically unable to perform list.
Herrera can't practice, but he can do conditioning drills and go through team meetings. He also had triceps surgery this offseason. He can be removed from the PUP list at any time during camp.
Cornerback Cedric Griffin went through practice as he attempts to return from torn ACLs in both knees over the past two seasons. Frazier said the Vikings will be cautious with him early in camp.
"We would love to have him back," Frazier said. "We've got to go slow here as we try to get him ready for the San Diego game."
Griffin declined to say if he would be ready for the Sept. 11 opener against the Chargers.
• Running back Adrian Peterson had to leave Monday after his fiancée went into labor. Frazier said he might miss a day or two.
• Vikings single-game tickets and multi-game packages go on sale at 9 a.m. Wednesday at the team's ticket office and at 10 a.m. through Ticketmaster. Anyone wanting to buy a ticket to the Oct. 23 game vs. Green Bay also will have to buy one for the Sept. 1 preseason game against Houston.
• Safety Madieu Williams, released by the Vikings last week, agreed to terms with San Francisco.