AceShowbiz -

Anna Kournikova's stint on "The Biggest Loser" is apparently short-lived. The tennis ace has confirmed to THR via her representative that she is leaving her post as a trainer on the NBC reality show after one season only.

"I enjoyed my time on the 'Biggest Loser' ranch. Although I will not be returning as a full time trainer on season 13, I will always be a part of 'The Biggest Loser' family and my commitment to bettering lives through health and fitness will continue," she said in a statement.

Kournikova's reason of exit was not disclosed but rumor has it, she has some issues with the staffers, and the contestants thought she was a bit brash. Her harsh method was often compared to Jillian Michael's which tends to sympathize on the contestants when they complain of the training being too hard. Someone on the show even called her "a nightmare".

But one contestant may disagree to these claims. Joe Mitchell, who was sent home from the Ranch on this week's show, told People that Anna was able to "fix" him. "Anna made me believe that I could [lose weight]," he said. "She drilled in our heads that the only person you can really rely on is yourself."