Johnson was walking onto the court after a timeout early in the game against the Florida State Seminoles when he collapsed, according to the ESPNU broadcasters. He was taken off the floor on a stretcher.
A group of visibly shaken teammates and coach Mike White huddled in prayer before play resumed, according to game footage.
The 6-5 junior forward from Norfolk, Virginia, was in critical but stable condition at Tallahassee Memorial Hospital, team spokesman Denver Parler said via Twitter.
Florida Gators men’s basketball tweeted, “Our thoughts are with Key. Love you, man.”
The team’s leading scorer and rebounder, Johnson is averaging 19.7 points and 6 rebounds per game. He had 5 points before collapsing.
Johnson was the Southeastern Conference Player of the Year.
Florida State won the game 83-71.