Cooper made the announcement Friday morning, saying that Stamkos was "unfit to play" in Game 4. The Lightning took a 3-1 series lead over the Dallas Stars with a 5-4 overtime win on Friday night. Game 5 is Saturday.
Stamkos had not played all summer before making his 2020 postseason debut in Game 3 on Wednesday. Stamkos scored on the first shot he took as the Lightning rolled to a 5-2 win. He became the first player in 80 years to score while playing his first postseason game of the year in the Stanley Cup Final.
However the 30-year-old Stamkos took only five shifts, totaling less than three minutes of playing time, and did not play in the second or third period. He said he was held out because he encountered "an issue." Stamkos remained on the bench with his teammates for the rest of Game 3 and took a few twirls on the ice during TV timeouts.
"There's been a lot of behind-the-scenes things that I'll be glad to share with you guys after the season," Stamkos said after the game. "We're focused on winning right now, and tonight was a step in the right direction."
Stamkos had not played in a game since Feb. 25 and underwent surgery to repair a core muscle injury on March 2. His expected recovery timeline was six to eight weeks, but he has had several setbacks. Cooper said when he inserted Stamkos into the Game 3 lineup that he didn't expect the captain to have any on-ice limitations.