Robert Williams was playing in just his 15th game of the season for the Boston Celtics on Saturday night in an Eastern Conference matchup against the Toronto Raptors. Unfortunately, the 25-year-old was forced to exit the contest in the first quarter after suffering a scary injury on his surgically repaired knee.

Celtics star Jaylen Brown fell on Williams’ left knee after a bit of a scramble. Sadly, it was the same knee that Williams has had two procedures on previously. The Celtics big man quickly exited the game after the freak accident:

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Williams was able to return to action after the knock, which seems to point to the fact that he’s doing fine. However, he was eventually ruled out for the remainder of the game. The 6-foot-9 center will get some tests done on the knee, and the results of the same should determine the extent of the injury. It’s officially being diagnosed as a hyperextended knee, so Celtics fans will definitely be hoping for the best here.

Williams wasn’t the only casualty from Saturday night for the Celtics either. Marcus Smart exited the game in the second quarter with a sprained left ankle and was helped to the locker room by the coaching staff, which obviously does not bode well for his status moving forward. Smart also spent some time lying on the floor as he got himself checked by the trainers.

Jayson Tatum was sitting this one out with a sore left wrist, so the injuries to Williams and Smart leaves Boston extremely shorthanded against Toronto.