Boston Celtics star Jayson Tatum suffered an apparent right leg injury in the fourth quarter of Monday night's 121-113 Game 4 loss to the New York Knicks.

Tatum sustained the injury while trying to secure a loose ball. The All-Star forward couldn't put any weight on his right foot and needed to be carried off the court.

Celtics head coach Joe Mazzulla said postgame that Tatum will undergo an MRI on Tuesday, according to Gary Washburn of The Boston Globe.

"The loss is the loss. More importantly, it's Jayson I'm worried about," veteran Al Horford told reporters postgame, per The Athletic's Jay King.

Tatum was having one of the best playoff performances of his career at the time of the injury. He had 42 points on 16-of-28 shooting to go along with eight boards, four assists, four steals, and two blocks in 40 minutes.

It was the fifth 40-point playoff game of Tatum's career. He also surpassed Derek Fisher for 12th on the NBA's all-time leaderboard for threes made in the postseason.

Tatum entered Monday's contest leading the Celtics in points, rebounds, assists, and steals through its first eight playoff games.

New York holds a 3-1 series lead heading into Wednesday's Game 5 clash in Boston.