NORMAN, Okla. (AP) – Heisman Trophy hopeful Adrian Peterson broke his collarbone on a dive into the end zone Saturday, and the Oklahoma star running back likely will miss the rest of the season.

Peterson was injured on his last carry of the game – a 53-yard scoring run with about 6:40 remaining that completed the 23rd-ranked Sooners’ 34-9 win over Iowa State.

Peterson ran for 183 yards and two touchdowns.

Peterson, a junior, who has 1,030 yards this season and entered the weekend as the nation’s fourth-leading rusher, was second in Heisman voting as a freshman.

He was playing for the first time in years before his father, who had spent about eight years in federal prison for money laundering.

“Just diving into the end zone and when he landed, he landed wrong,” Oklahoma coach Bob Stoops said. “At this point it looks like the best thing, the earliest he would be ready to play, would be a bowl game.”

Sooner quarterback Paul Thompson said the team will have to find a way to keep going.

“A.D. is the focal point not only of this offense but the team,” Thompson said. “It’s big, so a lot of guys are going to have to step up. Not just other running backs.

“This team as a whole is going to have to step up and pull an extra load.

“He was obviously a great back, one of the best backs in the nation.”

Peterson set an NCAA freshman record with 1,925 rushing yards in 2004 as he helped lead Oklahoma to the BCS title game, where the Sooners lost to Southern California. He had rushed for at least 100 yards in 22 of his 30 games at Oklahoma, including nine straight to start his career.

His performance Saturday moved him into fourth place on Oklahoma’s all-time rushing list. He would need only 150 to match 1978 Heisman Trophy winner Billy Sims’ total of 4,118 yards.

“I’m still not even trying to think about an offense without him, but I guess it is reality,” receiver Malcolm Kelly said. “We’re going to have to come out and play, man. Everybody came here to play football, and that’s what we’re going to have to do. We’re going to have to do it to a higher level than we’ve been doing.”

Despite all that success, Peterson had been fairly injury-prone in his Oklahoma career. He dislocated his left shoulder in fall practice in 2004, reaggravated it during the regular season and then had surgery in the offseason.

He missed one game last season and was severely limited in three others with a sprained right ankle.

Peterson’s backup is Allen Patrick, another I-back style runner. Jacob Gutierrez, a Quentin Griffin-style back who helped fill in for Peterson after his injury last season, is also an option.

“We won’t make any rash decisions,” offensive coordinator Kevin Wilson said. “I don’t think the offense is going to change dramatically.”

AP-ES-10-14-06 1713EDT