The Celtics will be without a key piece for a win-or-go-home game.

Jayson Tatum will miss Game 7 against the 76ers on Saturday night due to a left leg injury, the Celtics announced.

Tatum was added to the Celtics’ injury report earlier in the day with left knee soreness and was considered questionable.

The 28-year-old exited with 4:03 left in the third quarter of their Game 6 loss on Thursday, and he did not return.

Tatum returned to the court in March after suffering a torn right Achilles in the second round of the playoffs last year against the Knicks.

He shook off most of the rust quickly, averaging 21.8 points, 10 rebounds and 5.3 assists in 16 regular season games.

His stats looked even better in the playoffs (23.3 points, 10.7 rebounds and 6.8 assists).

But if Boston wants a Knicks rematch, it’ll have to do it without a six-time All-Star.