Danny Ainge, the Boston Celtics' president of basketball operations, suffered a mild heart attack in Milwaukee on Tuesday night, the team announced.
According to a release from the team, Ainge received immediate medical attention, is expected to make a full recovery and will return to Boston shortly.
"Been in constant communication with his family," Celtics coach Brad Stevens said Thursday. "He's resting well and feels better. Obviously, always scary, but he's got a good support network. Obviously, expect a full recovery and he's feeling good. So that's all positive. Certainly scary."
Ainge, 60, also suffered what was described as minor heart attack in 2009.
Ainge was in Milwaukee to watch the Celtics' Game 2 loss to the Bucks in the Eastern Conference semifinals.
Game 3 of the best-of-seven series is Friday night in Boston.
"What he's going through is more important than any game we are playing," Celtics forward Jayson Tatum said. "He's doing better and I know he wants us to go out and compete. Game 3 is important to us and very important to him and everyone in our organization."
Ainge was a two-sport star at BYU who in 1981 won the Wooden Award as the nation's top college basketball player. He played parts of three seasons with the Toronto Blue Jays, batting .269 before settling into a 14-year career in the NBA.
Ainge was an All-Star in 1988 and won two championships with the Celtics with the original Big Three of Larry Bird, Robert Parish and Kevin McHale.
Ainge coached the Phoenix Suns for three-plus seasons and took over the Celtics' basketball operations in 2003. He was the NBA executive of the year in 2008, after engineering the deals for Kevin Garnett and Ray Allen that helped the Celtics raise their unprecedented 17th NBA championship banner.
"Danny is just one of those guys who takes time out of his life, his day when he's doing his schedule, to make sure you're all right," Celtics guard Marcus Smart said. "He constantly checks in on us, my family, and things like that. Just personally, for me, he's been another mentor. For me, from when I first got here, Danny was the person I see every day and am talking to, so he means a lot to my life as well. ... I just hope he has a speedy recovery."
ESPN's Tim Bontemps and The Associated Press contributed to this report.