Mardy Fish has pulled out of next week’s event in Memphis due to ongoing heart issues, the tournament reported. Memphis was supposed to be the 30-year-old’s first tournament since he withdrew from his fourth-round match against Roger Federer at last year’s U.S. Open.

Fish recently served as a hitting partner for the U.S. Davis Cup team in its tie against Brazil, and was said to have engaged in full practice sessions there. His potential return date is unknown.