It wasn't that the Kansas University football team didn't expect the offensive blitzkrieg it got from fourth-ranked Oklahoma on Saturday in Norman.

It was just that, against one of the country's top programs, the Jayhawks' lack of defensive depth - especially in the secondary - proved too much to overcome.

"We have a lot of guys that are on the field and never come off on defense," Kansas coach Mark Mangino said following his team's 45-31 loss to the Sooners. "(Safety Darrell) Stuckey hardly ever leaves the game; (safety Justin) Thornton hardly ever leaves the game. A lot of the defensive linemen, they're playing a lot of reps there."

In their worst defensive showing to date, the Jayhawks gave up 674 yards of total offense, the most since 1988, and Sooners quarterback Sam Bradford looked every bit the Heisman candidate he's hyped to be, completing 36 of 53 passes for 468 yards and three touchdowns en route to breaking Oklahoma's single-game passing record.

It didn't help Kansas' defense, of course, that the Sooners won the time-of-possession battle by nearly 10 minutes, 34:13 to 25:47. Or that the game stretched four hours, Kansas' longest game this season. Or that, thanks to a Jayhawks offense that scored in under two minutes on each of its five scoring drives, the defense didn't get all that much time to recuperate on the sidelines.

"You go into a game, you know you're going to be like that," said Stuckey, who recorded a career-high 12 tackles against the Sooners. "So you try to prepare yourself. Sometimes, regardless of what you do, you can't prepare yourself. You can't change your body's limits. So it's one of those things where you go out there and you fight as hard as you can, and you put it all on the field."

With five regular-season games remaining and the conference race beginning to take shape, Kansas (5-2, 2-1 in the Big 12) is focused on remedying the situation quickly. Several young players, including true freshman Corrigan Powell, are being groomed to handle larger roles in the team's secondary, and Mangino said after Saturday's game that some of the team's younger reserves should be able to contribute in the near future.

They'll likely need to, especially considering the Jayhawks' next opponent is No. 8 Texas Tech, which leads the country in passing offense with 418.4 yards per game.

"You just try to get them better," said Mangino, whose team fell to No. 19 but is currently alone in first place in the Big 12 North. "We've been working with some younger kids we think are on the cusp of helping us. We'll see. You can't put them out there if they're not ready, but I think we're close with some kids."

Crawford offers 'fresh' look: Kansas reserve running back Jocques Crawford might have done enough in one game as a kick returner to take over the permanent role of starter from incumbent Marcus Herford.

In addition to a number of other personnel changes on special teams, Mangino started Crawford in an effort to shake up his kick-return unit, which entered the game ranked last in the NCAA Bowl Subdivision in kick-return average with just 12.38 yards per return. Crawford didn't disappoint, returning three kicks for 77 yards, including a 42-yard burst on his first return of the game that marked the longest of the season for the Jayhawks.

Mangino said afterward that he liked what he saw, but also added that Herford would remain a future option at the position.

"I equate it to bringing in a new pitcher from the bullpen, maybe a guy that's throwing different stuff to keep them off balance," Mangino said Sunday. "... Marcus will always be ready. He practices back there. We'll probably use him again this season. But for right now, with the way we're blocking things and the personnel we have there, Jocques, he's kind of fresh back there. He's a fresh look."

Run game hits its stride: For the second straight week, Kansas' ground game was able to act as a viable complement to the team's established passing attack.

Despite being forced to throw for much of the second half, the Jayhawks ran for 134 yards and two touchdowns, led by running back Jake Sharp's 12-carry, 103-yard performance - his second consecutive game with more than 100 yards on the ground.

"We need the run game to work well for us. We really do," said Mangino, who said the Oklahoma game was probably the best the Jayhawks had run between the tackles all season. "We're always a better team when we have a little bit more balance."