"American Idol" judge Paula Abdul says she is "not sure" if she will be returning to the popular U.S. TV series for another season.

Newsday said Friday while appearing on CBS' "Late Show with David Letterman," Abdul joked around about her approach to judging a ninth season of the Fox TV competition.

"I never said (I wasn't returning). I just said that I'm not sure," Abdul told Letterman Thursday night.

"It's called, um, 'negotiating,'" she added.

Letterman offered Abdul a bit of advice by detailing a decision he made earlier in his career, which included hosting duties on NBC's "Late Night with David Letterman."

"One time, I tried that, I was coming up to the end of a contract, and I said, 'I don't know, maybe I won't come back,' and they said, 'Fine because we've got another guy ready to go,'" Letterman told Abdul.

The ninth season of "Idol" is not scheduled to begin until 2010.