Andy Murray out indefinitely with pelvic injury setback

Specifically, the 33-year-old explained that he is battling tendinitis in his left psoas. Per Reuters (h/t ESPN), that muscle connects the lower back to the top of the leg.

"It's been kind of on and off since the U.S. Open," Murray said in a video uploaded to his Facebook page. "I've been trying to deal with it in training, and in the matches, and unfortunately after my match here this week it's flared up again.

"I've been practicing the last few days and trying to manage it, but after playing some points today, I decided that it was not going to be good enough to play."

Murray underwent a hip operation in January 2018 and again in January 2019, and the two-time Wimbledon champion who won the 2012 U.S. Open missed this year's Australian Open and ATP Cup due to a pelvic problem. He returned to competitive play at the Western & Southern Open in August and fell in the third round of that tournament. 

Murray received wild-card entries into this year's U.S. Open and the French Open that was postponed to the fall because of the coronavirus pandemic. He lost to Felix Auger-Aliassime in the second round at Flushing Meadows and was bounced from the French Open in the opening round.