Russell Westbrook underwent arthroscopic surgery on his right knee on Wednesday, the Thunder announced in a press release.

The team described the procedure as proactive after Westbrook experienced inflammation in his knee this past weekend. He will be re-evaluated in four weeks and could miss the preseason.

Here’s the full release from the Thunder. pic.twitter.com/9wrj0O8NjQ — Brett Dawson (@BDawsonWrites) September 12, 2018

It is unclear how Westbrook suffered the injury, but he has been seen in recent weeks playing pick-up games in Los Angeles and New York as he played with C.J. McCollum and Enes Kanter last week.

As Westbrook will be re-evaluated in four weeks, he likely won’t play much—or at all—during the team’s preseason slate of games which kick off on Oct. 3 against the Pistons.

Westbrook missing training camp and the preseason may not necessarily be a huge blow to the team, but it will be interesting to see if he’ll be ready for the regular-season opener on Oct. 16 at Golden State.

The team will likely not want to rush Westbrook back from surgery so it is possible he’ll miss the start of the regular season if he and the team deem he is not ready to return.

The timing of the surgery is a bit unfortunate for Westbrook and the team with training camp set to begin in less than two weeks, but it’s obvious having the surgery now is better than during the middle of the season.

Westbrook has previously undergone three surgeries on his right knee that limited him to just 46 games during the 2013-14 season and he also missed some time the following season after breaking a bone in his hand.

Since the 2014-15 season, though, Westbrook has played in at least 80 games in each of the past three seasons and has mostly avoided any sort of injuries since then.

The Thunder have four games this preseason.