Former Alabama player Mikhail Torrance collapsed at a workout Friday and was taken to Blake Memorial Hospital in Bradenton, Fla., a source confirmed to ESPN.
He was transferred to the intensive care unit at Sarasota Memorial Hospital and was in critical condition, breathing with the aid of a ventilator.
AOL Fanhouse first reported the story.
Torrance had been training at the IMG Academies when he lost consciousness, a person who spoke on condition of anonymity told The Associated Press because the player's family had not authorized the release of any information.
Emergency medical personnel began working on Torrance within two minutes, and performed CPR as he was being taken to a hospital.
IMG spokesman Chris Ciaccio confirmed Torrance had been training at the facility Friday and had to be taken to the hospital, but had no other immediate information.
Torrance said earlier this summer that he was diagnosed in 2009 with an enlarged heart, which is why he believes he went without being chosen in this year's NBA draft. He signed a summer-camp deal with the Miami Heat, but was with the organization less than a week and never participated in any on-court drills or summer league games.
Torrance, 21, had been planning to spend the coming season overseas with Maccabi Tel Aviv, agreeing to a contract with the Israeli team last month. He led Alabama in points (15.6 per game), assists (162) and minutes (1,043) last season as a senior.
"I was shocked and saddened to hear about Mikhail this afternoon," Crimson Tide coach Anthony Grant said in a statement. "My thoughts and prayers are with him and his family at this very difficult time. I want Mikhail and his family to know that his teammates, coaches and the entire university community are praying for his full recovery."
Earlier this summer, he told The Birmingham News and Mobile Press-Register that team doctors at Alabama cleared him to play and said his heart condition was common to athletes.
Telephone calls placed to his parents' home Friday evening went unanswered.
The Associated Press contributed to this report.