Patrick Dempsey once again hinted that he may be ready to turn in his scrubs and exit the ABC series Grey's Anatomy.

The actor, who plays Derek Shepard in the medical drama, will complete a decade-long run on the show in the upcoming 10th season. During his Aug. 26 visit to The Late Show, host David Letterman asked him how much longer he will remain on the show.

"I think it depends on renegotiations, quite honestly," Dempsey replied. "I could stay, I may go, who knows?"

Dempsey was among the stars who signed new two-year deals in May 2012 to return to Grey's through season 10, including Ellen Pompeo, Justin Chambers, James Pickens Jr., and Chandra Wilson. Sandra Oh, who also signed the two-year deal, for her role as Dr. Cristina Yang, announced earlier in August that she will leave the show after the upcoming 10th season. She will give up her part on the show as Owen Hunt's (Kevin McKidd) on-again, off-again girlfriend and Meredith Grey's (Pompeo) best friend.

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Dempsey has previously talked about leaving Grey's Anatomy, most recently in July at the 2013 Television Critics Association Press Tour in Beverly Hills where he was promoting his new Velocity documentary series Racing LeMans. He spoke of the exhaustion that stems from playing the same character for more than nine years and said he gets more of a thrill by race car driving, which is a passion of his.

"When you're in a long show, there's less discovery and more of an endurance of having to be present," Dempsey said at the time. "I'm not necessarily bored with the show, I'm very grateful that I have a show that's on for 10 years...[now] it's about surviving."

"There's not a lot of homework that goes into it. You try to be present and not get caught acting," he added. "I'm grateful I have the gig, but it's not the same thing as being in a race car."

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Grey's Anatomy returns for a two-hour season 10 premiere on Thursday, Sept. 26, at 9/8 p.m. Central on ABC.

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