Boris Becker showed up at a U.S. Open practice court with what appeared to be an extraordinarily nasty case of tennis elbow.
The former number-one ranked tennis player, who won the Grand Slam event in 1989 and is at the tournament as Novak Djokovic's coach, was seen sporting the golf ball-sized bump on his left arm.
But the former German star's injury might not be tennis related at all since he is a right-handed player.
The 46-year-old Becker's massive elbow was observed as he watched his Serbian protege breeze past Argentine player Diego Schwartzman 6-1, 6-2, 6-4 on Tuesday.
Tennis elbow is a condition that causes pain and inflammation around the outside of the elbow. It is caused by the overuse of the muscles of the forearm and lasts between six months and two years.
Here's hoping the former tennis great is okay.