Boston Celtics center Robert Williams III suffers knee injury, out indefinitely

An MRI on Monday morning revealed that Boston Celtics center Robert Williams III suffered a meniscus tear in his left knee during Sunday afternoon's win over the Minnesota Timberwolves, the team announced.

Williams left Boston's 134-112 victory with 2:46 left in the third quarter. The Celtics are continuing to evaluate the severity of the meniscus tear before offering a timetable for Williams' return later this week. ESPN's Adrian Wojnarowski reported Williams is expected to miss a minimum of "several weeks."

"He said it wasn't even a specific play that he remembers," Celtics coach Ime Udoka said after the win, "but [he] came out of the game ... obviously went back to get checked out and was in quite a bit of pain."

Udoka told reporters prior to Monday's game against the Toronto Raptors that Williams would require surgery and was weighing several options. The Celtics coach did not rule out the possibility of a return.

"There are some that keep you out longer than others," he said, "and we're hoping for the best."

The injury occurred just as the Celtics, who were sub.-500 and clinging to the final play-in tournament berth on Jan. 21, moved into the No. 1 seed in the Eastern Conference. They are 24-4 over the last third of the season, owners of the league's best net rating (116.4) by seven points per 100 possessions in that span.

Williams has been an invaluable member of Boston's league-best defense. Their turnaround coincided with the athletic big man's reassignment to a roving role that called for him to challenge corner 3-pointers and protect the rim. Of 291 players who have defended 325 or more field-goal attempts this season, Williams has made the greatest statistical impact, forcing his opponents to shoot 6.9% worse than their averages.

Robert Williams III has been the anchor of the Boston Celtics' NBA-best defense. (Maddie Malhotra/Getty Images)
Robert Williams III has been the anchor of the Boston Celtics' NBA-best defense. (Maddie Malhotra/Getty Images)

Williams is on the short list of Defensive Player of the Year candidates. It will will be challenging for Boston to replace his ability to erase mistakes. Williams' verticality opens the floor offensively nearly as much as he closes it on defense. Also an underrated passer, he has averaged 10 points (73.6% shooting from the field), 9.6 rebounds, 2.2 blocks and a pair of assists in 29.6 minutes over 61 starts this season — all career highs.

Boston's reacquisition of center Daniel Theis is crucial to bridging the gap for Williams' possible return. Theis, who started over Williams on the Celtics' 2020 Eastern Conference finals run, is averaging 5.3 points (72.7% on 2-pointers), 4.1 rebounds and a block in 13.9 minutes over 14 games since rejoining his former team. How much his experience and effort can make up for the loss of Williams' impact remains to be seen.

Of equal importance to Boston's pursuit of a championship this season is the long-term health of their 24-year-old rising star. Williams fell to the 27th pick in the 2019 draft because of concerns about the potential for chronic injuries to both of his knees. He entered the league with lingering left knee tendinitis and has dealt with left knee soreness throughout a career limited to 174 appearances in four precautionary seasons.

Williams signed a four-year, $48 million rookie scale contract extension in August that begins next season.

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Ben Rohrbach is a staff writer for Yahoo Sports. Have a tip? Email him at or follow him on Twitter! Follow @brohrbach