Charles, also a track star, won the Big 12 100-meter dash in 2006 with a time of 10.23 seconds.
"He has the best speed of any player we'll see all year,” said defensive coordinator Brent Venables.
Charles has rushed for 543 yards and seven TDs, averaging 5.3 yards per carry.
• Sweet Sweed: One of the other keys for OU's defense will be containing Texas' 6-foot-5 wideout Limas Sweed, who leads UT with three TD catches.
But OU's defensive backs are confident they can match up with Sweed, largely because they face 6-4 Malcolm Kellyevery day in team drills.
"Sweed is a great player,” cornerback Reggie Smithsaid. "But we get pretty good practice with Malcolm.”
• Wright side of the river: OU defensive backs coach Bobby Jack Wrightknows what the OU-Texas rivalry is like wearing burnt orange. Wright spent 11 seasons as an assistant coach at Texas before joining Bob Stoops' staff in 1999.
"When I was south of the Red (River), I got cussed by people north of the Red,” Wright said. "Being born and raised in Texas, I have a lot of friends in Texas.
"I get cussed by them now.”
• The real McCoy: OU defensive tackle Gerald McCoyis one of many Sooner players who had a rooting interest in the Red River Shootout growing up
McCoy, who is from Oklahoma City, still recalls attending the 2004 game, when OU won 12-0.
"It was just a great game to watch,” McCoy said. "It was an amazing sight. It's going to be a lot of fun playing in. I can't wait.”
• Tough to tackle: Venables said he hopes his defense improves on its tackling from last weekend's 27-24 loss to Colorado. Venables said that although the defense had just eight missed tackles against the Buffaloes — second fewest this year to North Texas — missed tackles on two plays led to big gains, including a TD.
"It was the worst tackling this season,” he said. "I was very discouraged we let the opportunity slip out of our hand, but resolved not to let it happen again.”
By