The Insider.com

Tennis star Anna Kournikova is reportedly leaving the NBC weight loss show The Biggest Loser after serving as a trainer for just one season.

• November 14, 2011Watch our Live Stream of the 'Twilight: Breaking Dawn' Premiere!
• November 14, 2011They Dated?! Surprising Hookups
• November 14, 2011GQ Men of the Year 2012
• November 14, 2011Pink Brings Baby to Red Carpet
• November 13, 2011What Happened in Vegas This Weekend [Pics]
• November 13, 2011Double Take! Celebrity Look-Alikes

According to The Hollywood Reporter, her departure comes after Kournikova clashed with staffers and was not seen as sympathetic to contestants who go on the show to experience dramatic weight loss. One source from the show described Kournikova to the magazine as "a nightmare" who definitely did not fit the profile of a life coach.

Kournikova was hired by NBC to be a trainer on season 12 of The Biggest Loser to replace Jillian Michaels, who left to host her own NBC spin-off show, Losing It With Jillian.

The retired Russian tennis player confirmed her departure to THR in this statement: "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."