Golden State Warriors guard Klay Thompson suffered a leg injury during a workout in Southern California on Wednesday, the team announced.

A source told ESPN's Adrian Wojnarowski that Thompson injured his lower right leg and is expected to undergo testing in the next few days to determine the severity of the injury.

Thompson missed all of last season after tearing the ACL in his left knee during Game 6 of The Finals against the Toronto Raptors. The Warriors were optimistic that Thompson, who has spent over a year rehabbing the injury, would come back at full strength heading into this upcoming 2020-21 season.

Warriors coach Steve Kerr said recently that while the Warriors didn't clear Thompson to scrimmage during their team bubble in San Francisco, he was pleased with the way Thompson's rehab was progressing.

"It was great to have him out on the floor, in the locker room," Kerr said in late September, during a video call with reporters. "Just his presence alone gave us a jolt of energy and excitement. Practice went well. This is the first practice coming off an ACL injury and a year and a half absence so I didn't expect him to be in top shape, in top form, and he was not, but he moved well and it's a good first step."

Thompson's latest setback leaves even more potential questions for a Warriors group that was confident it could contend again next season in what is expected to be a loaded Western Conference race. The Warriors have the second pick in Wednesday night's NBA Draft.

There was a genuine sense of shock and disbelief throughout the organization after news of Thompson's latest injury swept across the league. The Warriors are just hoping the tests on Thompson's leg come back clean and he can come back to the floor with longtime teammates Stephen Curry and Draymond Green.