BERKELEY, Calif. (AP) California tailback Jahvid Best sustained a concussion and was taken to the emergency room after he leapt high into the air, flipped over a defender and landed on the back of his head in the end zone.

Best briefly lost consciousness following the terrifying fall from at least 5 feet, coach Jeff Tedford said after No. 23 Cal's 31-14 loss to Oregon State.

Tedford said initial tests had come back normal.

Best had movement in all of his extremities, Cal spokesman Herb Benenson said. Benenson also said that a preliminary evaluation showed Best sustained a concussion, but more tests were being done before a final diagnosis would be announced by the school. Tedford didn't know whether Best would be kept in the hospital over night.

Best's helmet came off on impact. He vaulted into the air over Oregon State safety Cameron Collins on the 7-yard touchdown run. Best's jersey was removed and he was wearing an oxygen mask when carted out of the stadium. Benenson said Best was taken to an emergency room for observation and examination.

Best missed practice Tuesday and Wednesday with a slight concussion sustained in the team's 23-21 win at Arizona State last Saturday, but participated in full during Thursday's workout. The concussion wasn't diagnosed right away.

Tedford said the fact Best has sustained two concussions in a week's span would be taken seriously.

''I'm sure that will be talked about,'' Tedford said. ''He will be evaluated very closely, no question about it. There's no way we'd take a chance with any of our players.''

The latest injury with 6:07 before halftime silenced Memorial Stadium, where fans chanted ''Jahvid! Jahvid!'' before everything went quiet. At least one family member was among those around the 20-year-old junior.

His teammates went down on their knees and waited, then moved to the end zone as trainers and doctors took him away on a stretcher. The game was delayed 13 minutes. Some of Oregon State's players who were on the field at the time huddled together in support.

Before play resumed, Tedford told his players Best was moving and assured them he would be OK.

''That took the worry off us. We were holding our breath and able to exhale,'' safety Sean Cattouse said. ''It was a hard moment for us to see Jahvid go down like that. There was silence. When he was staying down there, it got scary.''

Best, one of the most dynamic running backs in the country and a preseason Heisman Trophy contender, has 16 touchdowns and 867 rushing yards this season for the Golden Bears, including 29 yards on nine carries Saturday. He also has 22 catches for 213 yards.

Cal quarterback Kevin Riley took a hard hit with 1:19 left in the first half and was helped to the sideline. He returned in the second half.