NORMAN, Okla. (AP) — For a team that lost one of the most prolific running backs in school history, Oklahoma sure doesn’t seem concerned.

While it would be a luxury to have Adrian Peterson back for his senior season, the Sooners don’t expect to miss a beat with a quintet of tailbacks being groomed to take his spot.

“No one can ever fill Adrian Peterson’s shoes,” said DeMarco Murray, a freshman who dazzled enough in the spring that coach Bob Stoops called him the team’s best big-play threat at the position. “All you can do as the next guys is just step up. I think that’s what we all have in mind. We’re not worried about Adrian Peterson.”

Peterson ran for 4,045 yards in his three-year career, including a school-record 1,925 yards as a freshman when he finished second in Heisman Trophy voting. He ranks behind only 1978 Heisman winner Billy Sims and Joe Washington in the Sooners’ storied history.

But Oklahoma hardly flinched after Peterson broke his collarbone midway through last season. Allen Patrick, Chris Brown and Jacob Gutierrez filled in for Peterson admirably, combining for 1,149 yards as the Sooners won six straight games.

A year earlier, Patrick and Gutierrez carried the run game after Peterson sprained his ankle — winning back-to-back games after the Peterson was rendered ineffective in a loss to Texas.

“I think we’re 8-0 without him. So in the end, we’re used to that,” coach Bob Stoops said. “That won’t be a factor for us in how we run our offense.”

Instead of focusing on how to replace Peterson, the Sooners have spent the months since their dramatic overtime loss to Boise State in the Fiesta Bowl determining the best quarterback among three unproven candidates: Sam Bradford, Joey Halzle and Keith Nichol.

Bradford won the right to be Oklahoma’s starting quarterback.

Bradford was the best of the three in practices and scrimmages. It was enough to give him the starting job.

“He has nice size and I think he sees well. And I think he can make all the throws, as far as deep and intermediate,” offensive coordinator Kevin Wilson said. “He can move well and plays on the run. I think he is probably one of the more composed guys.”

The entire receiving corps is back, along with two proven tight ends and four of the five starting linemen. The vacated line position will be filled by the mountainous Phil Loadholt, a 6-foot-8, 350-pound junior college transfer.

On defense, it’s not so clear-cut. Top tacklers Rufus Alexander and Zach Latimer are gone at linebacker, and the three top defensive ends have also moved on. The strength of the unit is a secondary that seems to be settling in after numerous position changes over the past two seasons.

Stoops likes the concept of splitting time among the running backs, believing that none of the five shares the same physical prowess and stamina as Peterson, the No. 7 pick by Minnesota in April’s NFL draft.

Patrick, a former defensive back, has shown he can outrun defenders and handle the starter’s role.