Tampa Bay Buccaneers offensive lineman Frank Okam cools off during a water break during a workout at NFL football training camp, Saturday, July 28, 2012, in Tampa, Fla. (AP Photo/Mike Carlson)

Washington Redskins defensive end Chris Baker sprays water on his face to cool off at an NFL football training camp practice at Redskins Park, Friday, Aug. 3, 2012, in Ashburn, Va. (AP Photo/Alex Brandon)

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)

St. Louis Rams defensive end Chris Long cools off between reps during the first day of NFL football training camp, Sunday, July 29, 2012, at the team's training facility in St. Louis. (AP Photo/Tom Gannam)

Jul 27, 2012; Cincinnati, OH, USA; Cincinnati Bengals center Kyle Cook (64) cools off during training camp at Paul Brown Stadium. Mandatory Credit: Frank Victores-US PRESSWIRE

Dallas Cowboys cornerback Brandon Carr rests in a tub filled with ice and water after practice during an NFL training camp Monday, July 30, 2012, at City of Oxnard Fields in Oxnard, California. (AP Photo/James D Smith)

Houston Texans' Logan Brock beats the summer heat with a cold spray of water during training camp Monday, July 30, 2012, in Houston. (AP Photo/Pat Sullivan)

July 28, 2012; Houston, TX, USA; Houston Texans wide receiver Andre Johnson (80) gets a drink of water during training camp at Methodist Training Center. Mandatory Credit: Brett Davis-US PRESSWIRE

Green Bay Packers linebacker Nick Perry (53) cools off during NFL football training camp Thursday, July. 26, 2012, in Green Bay, Wis. (AP Photo/Mike Roemer)

Green Bay Packers linebacker Clay Matthews (52) sprays water on his face to cool down during NFL football training camp, Tuesday, July 31, 2012, in Green Bay, Wis. (AP Photo/Mike Roemer)

July 30, 2012; Ashburn, VA, USA; Washington Redskins quarterback Robert Griffin III (10) squirts water on his face during Redskins training camp at Redskins Park. Mandatory Credit: Geoff Burke-US PRESSWIRE

Carolina Panthers' Andre Neblett cools off during practice at the NFL team's football training camp in Spartanburg, S.C., Monday, July 30, 2012. (AP Photo/Chuck Burton)

Houston Texans' Duane Brown cools off during NFL football training camp on Sunday, July 29, 2012, in Houston. (AP Photo/Pat Sullivan)