Jayson Tatum will have an MRI on the lower leg injury he suffered during the Boston Celtics’ 121-113 Game 4 defeat against the New York Knicks on Monday.

Tatum suffered what appeared to be a serious lower leg injury late in the fourth quarter. He writhed in pain on the court, had to be carried off by Celtics staffers and was seen on ESPN’s broadcast riding in a wheelchair after exiting down the tunnel.

The Celtics’ offense is at its best when all five players are aggressively attacking the rim, spraying the ball out to open shooters and scrambling opposing defenses. It’s hard to do that when one player—Holiday in this case—removes himself from the action.