The Boston Celtics said rookie point guard Payton Pritchard will be off the court for at least two weeks after suffering a Grade 1 MCL sprain in his right knee during Friday night’s 122-110 loss in Philadelphia to the 76ers.

Pritchard needed to be helped off the court after Jaylen Brown fell into his leg in the second quarter. The Celtics ruled him out for the rest of the game a short time later. Pritchard eventually rejoined his teammates on the bench.

The 26th pick in November’s NBA draft, Pritchard has been a revelation for the Celtics, instantly carving out a spot in coach Brad Stevens’ rotation. He is averaging 7.7 points while shooting 42.5% from 3-point range.

His outside shooting has been a welcome addition to a Celtics team that has dealt with Kemba Walker missing the first few weeks to recover from an offseason strengthening program for his left knee, and forward Jayson Tatum has missed the past several games due to the NBA’s health and safety protocols.

Tatum was ruled out of Sunday’s game against the Cleveland Cavaliers as he remains in the league’s protocols. The game will mark his fifth straight on the sidelines. There was no indication as to whether Tatum would remain out for Monday’s game in Chicago against the Bulls.

In addition to Tatum and Pritchard, the Celtics will continue to be without second-year forward Romeo Langford, who has yet to play this season after undergoing offseason surgery on his right wrist. Rookie forward Aaron Nesmith is doubtful with lower back spasms.

Boston will be looking to snap a three-game losing streak Sunday, one that comes on the heels of a five-game winning streak that had pushed the Celtics to the top of the East standings.