Despite the initial denials issued by the show amid the latest rumors of on-set upheaval, the revolving door that is the Grey's Anatomy cast has taken another sudden and surprising spin, reports the reliable Michael Ausiello of Entertainment Weekly.

In a shocking development, sources are now confirming that T.R. Knight (George O'Malley) has asked to be released from his contract, a request that both ABC and Grey's Anatomy creator / executive producer Shonda Rhimes appear poised to grant.

"They're working out the details now," whispers an ABC insider.

There's no word on when T.R. Knight would make his final appearance, but, contrary to a report on the gossip blog crazydaysandnights.com, he has not walked off the set of the show: "He's still working," maintains EW's Grey's Anatomy mole.

Rumors of Knight's unhappiness with Grey's Anatomy date back to Isaiah-gate. The actor was reportedly upset that despite Patrick Dempsey and Katherine Heigl rallying to his defense, it took Rhimes so long to publicly condemn Washington's now-infamous use of the F-word.

The incident led T.R. Knight to come out as a gay man.

Rhimes eventually released a statement denouncing Washington's behavior, but word is, it was too little, too late. Nonetheless, a Grey's Anatomy source insists Knight does not want out of his contract for that reason, adding, "He just feels it's time to move on."

A spokesperson for T.R. Knight declined to comment.

T.R. Knight's probable exit comes at a time when his character, George, has been given little to do of late, save for express concern over Izzie's mental state.

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.