A football player on Northwestern's co-Big Ten championship team last season collapsed and died Friday during conditioning drills, the university said.

Initial medical reports indicated Rashidi Wheeler, 22, did not die of heat-related causes, the school said, adding that an autopsy would be conducted. A spokesman for the Cook County Medical Examiner's office also said he didn't believe the death was heat-related because temperatures were in the low 80s in the Chicago area Friday.

Wheeler's death came two days after Minnesota Vikings tackle Korey Stringer died of heat stroke after an intense practice in stifling humidity and temperatures in the 90s.

A senior sociology major, Wheeler started all 12 games last season at strong safety. His 88 tackles were third on the Wildcats. He had a fumble recovery and three pass breakups. He played in eight games as a sophomore and five games as a freshman.

"This is a terrible tragedy for Rashidi's family and for the team," said Wildcats coach Randy Walker. "A sudden loss like this is difficult to comprehend."

Before Northwestern, Wheeler starred at Damien High School in Ontario, Calif., where he lettered in football, track and basketball.

"Our hearts go out to Rashidi's family at this time," Northwestern's athletic director Rick Taylor said. "I'd like to express our deepest sympathies and our condolences."

A Northwestern trainer was present at the drills and administered first aid and CPR when Wheeler collapsed, the school said. Evanston Fire Department paramedics were summoned to the scene.