The Celtics announced Monday that forward Jae Crowder sprained his left ACL during Sunday's season-ending Game 4 loss to the Cavaliers.
Crowder's injury is not expected to require surgery.
The 24-year-old Crowder, acquired as part of the trade that sent Rajon Rondo to Dallas in December, will be a restricted free agent this summer after the Celtics formally extend a $1.2 million qualifying offer. Boston will have the ability to match any offers that Crowder receives, and president of basketball operations Danny Ainge has often repeated that Crowder is part of the Celtics' future plans.
Crowder was injured Sunday when J.R. Smith delivered a backhand strike to Crowder's face while the pair jockeyed for a rebound. Crowder fell backward with his knee bending awkwardly as he hit the floor. Smith was assessed a flagrant-2 foul and ejected with 10:27 left in the third quarter.
Smith could receive further discipline from the league upon review of his infraction.
Celtics players said after Sunday's game that Crowder was able to walk under his own power. His teammates were hopeful that Crowder will be back with the team next season after emerging as a quiet leader during Boston's playoff push.
"Jae doesn't really speak much, but he leads by example," Celtics guard Avery Bradley said. "Every single day he comes in, he plays hard, and you saw him [Sunday] -- he gave it his all, he went out there and fought, he got the crowd into it, and he got us into it.
"It was unfortunate that he got hurt and had to leave the game, but Jae Crowder is definitely a competitor, and this entire year he's been helping our team out every single game."