Boston Celtics center Robert Williams III to miss Game 4 against Milwaukee Bucks with sore knee 6:28 PM ET Andrew LopezESPN BOSTON -- The Boston Celtics ruled Robert Williams III out of Monday's Game 4 against the Milwaukee Bucks with left knee soreness. Williams had not appeared on any of Boston's injury reports, but coach Ime Udoka said Williams tried warming up pregame and felt the soreness was too much. "He had some soreness today," Udoka said. "Just kind of flared up. Came out of nowhere. He didn't feel anything yesterday or during the game. It wasn't an incident. Just a little flare-up, it got irritated trying to warm up." Editor's Picks 1 Related Williams tore the meniscus in his left knee in late March and didn't return to the lineup until Game 3 of Boston's first-round series against the Brooklyn Nets . Against Milwaukee, Williams returned to the starting lineup, and he has started all three games. Udoka said that it's not unexpected that Williams would have soreness because of the surgery, and that he'd had general soreness between games but this time is more pronounced. Udoka said he didn't expect Williams to undergo any further testing but was hopeful he'd be ready to go for Game 5 in Boston on Wednesday. "You would expect so," Udoka said when asked about Williams' potential availability. "He's had some natural soreness. ... It's expected to calm down and he can get back out there for next game." In the Bucks series, Williams averaged 8.7 points, 5.7 rebounds and 2.7 blocks per game. He missed some time in Game 3 after getting hit in the head with an elbow from Bucks forward Bobby Portis . With Williams out, Boston will start Grant Williams in his place.