Isaiah Thomas on Celtics' Robert Williams Playing on Knee Injury: 'Heard That Before'

Isaiah Thomas has a warning for Robert Williams III: Be careful playing through injuries the Boston Celtics say can't get worse.

Thomas famously played for the Celtics despite an injured hip during the 2016-17 season and aggravated the injury during the 2017 playoffs. The injury forever altered his career, with Thomas never returning to the All-NBA form he showed that season.

Playing through injury also likely cost Thomas tens of millions in future earnings, as the 2017-18 season was the final year of his contract. The Celtics traded Thomas to the Cleveland Cavaliers during the 2017 offseason, and the two-time All-Star has subsequently bounced around to six different NBA teams and had a stint in the G League while undergoing several procedures to fix his ailing hip.

Williams suffered a torn meniscus in March and returned in less than a month to aid in the Celtics' postseason run. While the center has been effective while on the floor, the 24-year-old revealed he's dealt with consistent pain in the knee and had to have fluid drained from the knee on several occasions.

“I was really having my knee drained a lot last series,” Williams told Chris Haynes of Yahoo Sports. “I stopped draining it because there was no point, in my opinion. My knee kept filling back up with fluid. So, I’ve kind of learned how to manage it to be able to play.”

Williams is the Celtics' most important interior defender, and you can see the difference in their defensive intensity when the All-Defensive second-team selection is on the floor. Boston's defensive rating improves by 7.1 points per 100 possessions when Williams is on the floor during the playoffs.

Unlike Thomas, Williams at least has some sort of long-term security. He is in the first year of a four-year, $48 million extension that lasts through the 2025-26 season.