The Boston Celtics are tied 2-2 in their Eastern Conference Semifinals series against the Milwaukee Bucks. After going 1-1 at home and 1-1 away, the Celtics are back playing host for Game 5. However, they got a rough injury update less than two hours before tip-off.

According to Ime Udoka, Robert Williams is out for Game 5 due to his ongoing knee injury. Celtics blogger Keith Smith tweeted the news Wednesday afternoon.

This is the second game in a row that Williams will miss because of left knee soreness. According to Smith, Grant Williams is expected to bear most of the brunt of Robert Williams' absence in Game 5.

He filled Robert Williams' starting position in Game 4, recording nine points and four rebounds in the Celtics' win to tie the series.

Although Grant Williams was the one who stepped in for Robert, Al Horford and Jayson Tatum were the biggest contributors in the Monday night win. Horford put up 30 points, eight rebounds, and three assists, while Tatum had 30 points, 13 rebounds, and five assists.

Robert Williams' final designation ahead of Game 5 could come as an unpleasant surprise for many Celtics fans. Roughly 24 hours beforehand, Williams was listed as questionable for Wednesday night.

His rectot injury more than likely stems from the torn meniscus he suffered in the regular season. The 24-year-old had surgery to repair his left knee back in March. However, Williams will now miss a second-straight game in the Eastern Conference Semifinals, and the injury is proving to be more of a long-term issue than once anticipated.