TOLEDO, Ohio - A Toledo basketball player who collapsed during conditioning drills died of a ruptured blood vessel to his heart, according to preliminary autopsy results released Tuesday.

Haris Charalambous, a backup center for the Rockets, was stricken Monday as players started some light running during a routine workout. His aortic arch ruptured, caused blood to fill the sac around his heart and stopped it from beating, said Dr. James Patrick, Lucas County coroner.

Several more weeks of testing will be needed to determine what caused the rupture, a well-known cause of sudden death, Patrick said.

“Even though the emergency response - what our trainers did was great - once the heart can't pump blood because of pressure around it, there's just not a very good likelihood that he is going to live,” said Dr. Roger Kruse, team physician.

Trainers performed CPR less than a minute after he collapsed, and 911 was called immediately, university officials said. He was pronounced dead at a hospital.

“Nothing can prepare you for this,” athletic director Mike O'Brien said. “I'm still in a state of shock. Our student-athletes, our athletic department staff and our entire campus has been stunned by this tragedy.”

The 21-year-old Charalambous, of Manchester, England, was expected to be a backup center this season. He played 23 games last season, averaging less than a point per game.

“The players are devastated. They're very emotional, losing a teammate and one of our basketball family members,” coach Stan Joplin said. “Haris is the ultimate team player. He was well liked by all of his teammates. He was a great person to be around.”

A memorial service was scheduled on campus today.

University officials planned to accompany Charalambous's body back to England later this week to personally express their condolences to his family.

An endowment in his name will be established to award a scholarship annually to a member of the men's basketball team, the school said.