Anna Kournikova leaves "The Biggest Loser"

(CBS) Anna Kournikova is out at "The Biggest Loser."

The tennis star is leaving NBC's weight loss reality show after spending one season as a trainer.

Kournikova's rep confirmed the news to The Hollywood Reporter on Monday.

"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.

According to THR, the 30-year-old clashed with staffers and did not sympathize with the overweight contestants. A source told the website that Kournikova was "a nightmare."

Kournikova was hired for Season 12, following Jillian Michaels' departure from the show.

"It wasn't the right fit for her," a "Biggest Loser" source told Us Weekly. "[Her exit] was a mutual decision."