Celtics general manager Danny Ainge believes four-time NBA champion Shaquille O'Neal will retire for good this summer.

"I think so," the Celtics' director of basketball operations replied when asked if he thought Shaq had played his last game in the NBA. "It's early to make those emotional decisions, but my guess is he has."

O'Neal played in just three games after suffering an Achilles injury on Feb. 1.