Columbia. Mo. ? Medical examiners will wait until today to release autopsy results for Missouri football player Aaron O’Neal.

The Boone County Medical Examiner’s office has completed the autopsy on O’Neal, who died Tuesday after collapsing on the field during a voluntary workout. A representative was expected to speak at a news conference late Wednesday afternoon on campus, but no one attended.

University officials blamed a scheduling conflict and continued to refer questions about the cause of death to the medical examiner’s office. Medical investigator Jessica Phillips declined to disclose the cause of death Wednesday, saying Medical Examiner Valerie Rao would not release the autopsy results until today.

Coach Gary Pinkel, who was out of town Tuesday when the 19-year-old O’Neal collapsed and later died, broke down several times during the news conference.

“This is just a devastating situation,” said Pinkel. “I feel like I lost one of my children.”

The death of O’Neal, a red-shirt freshman fighting for playing time as a middle linebacker, again has cast the spotlight on summer football workouts – programs that by NCAA rules are not overseen by coaches but rather by strength and conditioning directors and athletic trainers.

The NCAA passed a series of stringent regulations governing summer workouts after the deaths of three Division One football players in the summer of 2001, including a requirement that those supervising the workouts be trained and certified in CPR and first aid techniques.

O’Neal’s death suggests that college athletics should take a closer look at such preseason workouts, said Bryan Smith, a former team doctor for the University of North Carolina at Chapel Hill who spent six years as chairman of an NCAA committee on sports safety.

Missouri football player Aaron O'Neal, left, strains during a drill as director of strength and conditioning Pat Ivey, far right, yells encouragement. O'Neal, 19, died after collapsing during the workout Tuesday in Columbia, Mo.

“Enough of these incidents have taken place that warrant further investigation by the NCAA,” said Smith, now a medical consultant to the Atlantic Coast Conference.

Smith delivered a similar call to action in 2002, when he was still chairman of the NCAA Committee on Competitive Safeguards and Medical Aspects of Sports.

“It is safe to say that the current model of voluntary activities that emphasizes strength and conditioning for student-athletes is not working,” he wrote in an editorial for The NCAA News.

Asked whether strength coaches and trainers could have done more to help O’Neal or more quickly identify potential health problems Tuesday, Pinkel stood by his staff.

“I believe in them 100 percent,” he said.

Pinkel said he spoke by phone with Northwestern football coach Randy Walker, who experienced a similar loss in August 2001 when team member Rashidi Wheeler collapsed and later died following a summer workout. Pinkel also attempted to call coach Bobby Bowden of Florida State, where a football player died in the summer of 2001.

The tougher NCAA rules passed a year later limit summer workouts to no more than eight hours a week during an eight-week period. A member of the athletic department’s medical staff – whether a team doctor or trainer – must be on the field, and that official has the “unchallengeable authority to cancel or modify the workout for health and safety reasons,” the rules stipulate.

The school’s strength coach, Pat Ivey, supervised Tuesday’s workout at Faurot Field. Ivey and other members of the strength and conditioning staff attended Wednesday’s news conference but declined to answer questions afterward.

Missouri football coach Gary Pinkel, right, and a few of his players leave a news conference after Pinkel spoke about the death of Tiger player Aaron O'Neal. Pinkel appeared Wednesday in Columbia, Mo.

O’Neal, 6-foot-3 and 220 pounds, started to struggle with conditioning drills about 45 minutes into the hour-long workout, during which players wore shorts, T-shirts and cleats but no helmets or pads. Temperatures at the time were in the upper 80s.

At the end of the workout, O’Neal lay on the turf as Ivey talked to the 11 remaining players. A trainer helped O’Neal to his feet, and a teammate helped him to the locker room as the other players left the field.

Team officials have canceled workouts for the rest of the week. Earlier Wednesday, Pinkel traveled to the St. Louis suburb of Creve Coeur to meet with O’Neal’s family.

Pinkel said that while he would reevaluate how summer workouts are conducted, he didn’t think the sessions should be blamed for his player’s death.

“We’re very comfortable with what we do,” he said. “If we didn’t do these things, I think we would have significantly more (injuries).”