Minnesota Vikings running back Adrian Peterson runs sprints as part of his rehabilitation at NFL football training camp on Friday, July 27, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings tight end John Carlson, runs the ball during practice at NFL football training camp, Friday, July 27, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings defensive end Jared Allen, left, and Minnesota Vikings offensive tackle and rookie Matt Kalil, right, run a play during practice at NFL football training camp, Friday, July 27, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings defensive end Jared Allen, right, and offensive tackle and rookie Matt Kalil, left, run a play during practice at NFL football training camp on Friday, July 27, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings running back Adrian Peterson, center, talks to the media at NFL football training camp on Friday, July 27, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings defensive back Antoine Winfield, left, signs autographs as he arrives for the morning walk-thru of NFL football training camp, Saturday, July 28, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings rookie offensive tackle Matt Kalil arrives to the locker room with a sound system in tow before the morning walk-thru of NFL football training camp, Saturday, July 28, 2012, in Mankato, Minn. As a rookie, Kalil is responsible for the music in the offensive line locker room.(AP Photo/Genevieve Ross)

Minnesota Vikings defensive tackle Kevin Williams (93) shares a laugh with Vikings defensive end Jared Allen (69) during the morning walk-thru of NFL football training camp, Saturday, July 28, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings defensive tackle Kevin Williams (93) lines up during a drill in the morning walk-thru of NFL football training camp, Saturday, July 28, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings kicker Blair Walsh takes part in drills with Vikings' rookies Corey Gatewood (30) and Chase Baker (62) during the morning walk-thru of NFL football training camp, Saturday, July 28, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings running back Toby Gerhart (32) signs autographs after the morning walk-thru of NFL football training camp, Saturday, July 28, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings tight end John Carlson, of Litchfield, Minn., gives an autograph to eight-year-old Aidan Gravelle, of Vernon Center, Minn., after the morning walk-thru of NFL football training camp, Saturday, July 28, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings special teams coordinator Mike Priefer, left, works with the players during the morning walk-thru of NFL football training camp, Saturday, July 28, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings rookie offensive tackle Matt Kalil arrives for the morning walk-thru of NFL football training camp, Friday, July 27, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings wide receiver Percy Harvin, right, signs autographs after the morning walk-thru of their NFL football training camp, Friday, July 27, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings running back Adrian Peterson (28) and wide receiver Percy Harvin arrive for the morning walk-thru of NFL football training camp, Friday, July 27, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings defensive end Jared Allen signs an autograph on the arm of seven-year-old Janae Caballero, of Albert Lea, Minn., after the morning walk-thru of NFL football training camp, Friday, July 27, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings defensive end Jared Allen lines up for a play during the morning walk-thru of NFL football training camp, Friday, July 27, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings rookie and offensive tackle Matt Kalil runs a play during the morning walk-thru of NFL football training camp, Friday, July 27, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings quarterback Christian Ponder, right, hands off the ball to Vikings running back Toby Gerhart, left, during the morning walk-thru of NFL football training camp, Friday, July 27, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings head coach Leslie Frazier, left, arrives with Vikings defensive back Eric Frampton for the morning walk-thru of NFL football training camp, Friday, July 27, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings assistant defensive coach Jeff Imamura, left, works with the players during the morning walk-thru of NFL football training camp, Monday, July 30, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

In this photo made Saturday, July 28, 2012, Minnesota Vikings wide receiver Percy Harvin (12) runs the ball during a punt return drill in the morning walk-thru of NFL football training camp in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings defensive end Nick Reed (66) douses his head with water during practice at NFL football training camp, Monday, July 30, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings wide receiver Percy Harvin (12) signs autographs after practice at NFL football training camp, Monday, July 30, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings rookie offensive tackle Matt Kalil makes a block during practice at NFL football training camp, Monday, July 30, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings defensive end Jared Allen, left, tries to get around Vikings rookie offensive tackle Matt Kalil (75) as Vikings quarterback Christian Ponder (7) prepares to throw during practice at NFL football training camp, Monday, July 30, 2012, in Mankato, Minn. (AP Photo/Genevieve Ross)

Minnesota Vikings wide receiver Jerome Simpson runs with the ball after making a catch as Vikings corner back Marcus Sherels, left, defends during practice at NFL football training camp, Monday, July 30, 2012, in Mankato, Minn. At back right is Vikings linebacker Solomon Elimimian (59). (AP Photo/Genevieve Ross)