In the latest health issue for surprise 2009 U.S. Open quarterfinalist Melanie Oudin, the tennis pro says her heart problems have returned, pushing back the start to her season.
Oudin, who upset Maria Sharapova during her upset-filled run at Flushing Meadows at age 17, wrote Thursday on Twitter that she ''will probably have to undergo another procedure'' for a heart condition.
Oudin also tweeted a photo of herself wearing a monitor on her chest.
She already had a heart procedure in November, when she said in an interview with The Associated Press that she had been experiencing occasional ''episodes'' of an accelerated heartbeat for more than a year, usually during - or right after - matches.
''I was convinced it was some sort of anxiety,'' she said then. ''It's been really frustrating. I played through matches having it, because I never really knew what it was. I would try to relax and take some deep breaths and let my body relax, and then I felt better. It kind of sounds like an anxiety attack.''
Oudin, a 23-year-old from Marietta, Georgia, has been ranked as high as 31st and is currently 165th. She hasn't competed in a WTA event since September.
In 2013, she was diagnosed with a muscle-damaging condition which may be caused by intense exertion.
In her posting on Twitter on Thursday, Oudin called the latest setback ''very disappointing.'' She added: ''But I know I'll get past this and become a better and stronger person for it.''
''So I have some bad news to share with you guys,'' Oudin wrote. ''My heart episodes have come back and that will delay my start even more to the year. I will probably have to undergo another procedure, but for the time being I have to wear a heart monitor to keep track of things.''