Celtics' Robert Williams III Ruled Out for Game 4 vs. Bucks with Knee Injury

Boston Celtics center Robert Williams III was ruled out for Monday's game against the Milwaukee Bucks due to left knee soreness.

Ime Udoka told reporters that Williams had a sore throat on Monday.

Williams was replaced by Grant Williams in the starting lineup.

It is a tough break for a Celtics team that is already down 2-1 in the series despite Khris Middleton missing the first three games as he recovers from an injury.

The Williams loss is a big deal. He averaged 9.6 boards and 2.2 blocks per game to go along with his 10.0 points per contest in 61 starts.

Williams has shot an impressive 73.6 percent from the field this season, thanks to his offensive impact. His real footprint is on the defensive side.

The Celtics have given up less than 100 points per 100 possessions with Williams on the court. When he sits, that jumps up to a defensive rating of 108.6.

Al Horford and Daniel Theis are both capable options for the Celtics. Boston will be without its best rim protector and one of the big men it can throw at Antetokounmpo because of the loss of Williams.

Should the Celtics survive the Bucks, it is something of a long-term concern. Williams missed the first three weeks of the playoffs because of a torn left meniscus, but came back for Game 3 in the first-round sweep of the Brooklyn Nets.

The Celtics season would be on life support if they lost in Game 4. If Boston can fight back into this series, the status of Williams' knee will be one of the main storylines to follow.