The Boston Celtics announced ahead of tipoff that starting center Robert Williams III is available to play in Game 4 of the Eastern Conference playoffs against the Miami Heat on Monday night. Williams sat out Game 3 due to chronic pain in his left knee. Boston, on the other hand, will be without guard Marcus Smart, who suffered a sprained ankle in Saturday’s loss.

Williams underwent surgery near the end of March to repair a torn meniscus in his left knee and did not return until Game 3 of the team’s first-round series against the Brooklyn Nets. His return, however, was cut short after he suffered a bone bruise in the same knee during Game 3 of the team’s second-round series against the Milwaukee Bucks.

Williams missed the final four games against the Bucks, but was finally cleared to play again for the Eastern Conference finals, and suited up for the first two games in Miami. It’s not clear if something happened during Game 2, or if Williams is dealing with continued pain from the previous injuries.

In any case, missing him in Game 3 proved to be detrimental as the Celtics lost 109-103 to fall behind 2-1 in the series. Getting him back for Game 4 will provide Boston with a boost in the frontcourt, and while Williams doesn’t always put up big numbers, he’s the best rim protector on the team and blocked five shots in the first two games of this series. Opponents cannot attack the basket in the same way when he’s healthy. On the other end, Williams is a big-time lob threat who gives the Celtics a vertical option around the basket, and an effective offensive rebounder.