Ereck Plancher, a Central Florida freshman receiver, collapsed after participating in the Knights' final voluntary offseason workout before Thursday's scheduled start of spring practice.
Central Florida trainers administered CPR and then attached a defibrillator to Plancher's body to try and shock his heart back into rhythm. Emergency medical personnel arrived and Plancher was loaded into a waiting ambulance.
But Plancher didn't make it. He was pronounced dead shortly after arriving at the hospital.
"Distraught is not the word for coach [George] O'Leary right now," athletic department spokesman Joe Hornstein told the Orlando Sentinel. "He's devastated."
Central Florida has postponed the start of spring drills.
Plancher is the fourth football from a Florida university to die after a workout since 2001. South Florida running back Keeley Dorsey collapsed and died Jan. 17, 2007. Florida freshman Eraste Autin died in July 2001 and Florida State freshman Devaughn Darling collapsed and died in February 2001.
The Sentinel has several related links, including the 911 call, a column by Mike Bianchi, Alan Schmadtke's On Campus blog entry, a photo gallery and college football deaths this decade.