Just what the producers of Grey's Anatomy need: more discord within the cast.

Series star Katherine Heigl has bowed out of contract talks after reaching a stalemate with producers over a salary dispute.

Sources told E! Online TV columnist Kristin Veitch that Heigl is angling for a salary bump that would put her on par with the show's other female stars, namely Ellen Pompeo and Sandra Oh,  both of whom were better known before the ABC hit launched.

Heigl apparently feels that she has become an integral part of the show and her star is on the rise. According to sources, Heigl's camp believes that, come the June release of her Judd Apatow comedy, Knocked Up, Heigl will be one hot commodity. (Think Steve Carell post-The 40-Year-Old Virgin.)

ABC confirmed to E! News that, dispute or not, rising star or not, Heigl isn't going anywhere. She's currently signed for three more years, through the show's sixth season.

"Katherine is an integral part of Grey's Anatomy and its success," the network said in a statement. "Fortunately, we have a long term contract to ensure she'll be with the show for several years to come."

"In recognition of her tremendous talent and value to the show, we recently approached Katherine with an offer to raise her compensation significantly above the terms of her current contract. We were surprised to see this gesture reported negatively in the press, and want to reassure fans that she will continue as Izzie Stevens."

Heigl, meanwhile, said she was "embarrassed that this has become a public matter and disappointed that [ABC's production unit] Touchstone felt it necessary to divulge private employment information."

In a statement, the actor added: "I had hoped I would be able to deal with this issue confidentially with my bosses. I dropped out of the renegotiation simply because I wanted to treat myself with the respect I was not getting from them. No matter how unhappy I am about their decision to respond to this publicly, I continue to be passionate about and committed to this character.”

Heigl's Dr. Isobel "Izzie" Stevens has become a major asset onscreen (she was nominated for a Golden Globe for Best Supporting Actress and shared the ensemble award from the Screen Actors Guild), but Heigl's offscreen behavior has been something of a distraction.

The 28-year-old was the most vocal cast member in the wake of Isaiahgate.

Heigl made frequent comments in support of costar T.R. Knight and against costar Isaiah Washington, who called Knight a "faggot" during an onset fracas last fall and then denied it following the Goldeon Globes.

"I'm not okay with it," she said before Washington sought treatment. "He needs to just not speak in public. Period...And I'm probably going to get in a lot of trouble for being that blunt."

While ABC denies that the current contract dispute is any sort of embodiment of behind-the-scenes turmoil, People reports Heigl is distressed that Washington's continued presence on the show seems to valued over her own.

Of course, the stalemate could be less about conspiracies and more about money.

Last June, Touchstone rewarded each of the Grey's Anatomy principal cast members with a cool $200,000 one-time bonus for a time slot well done.

At the time, it was reported that the bonuses were an attempt to head off actors' requests for bigger paydays down the line. Apparently the powers that be wanted to avoid the inevitable salary battles that occur when relatively unknown stars are catapulted to fame via a monster hit show and try to renegotiate their original deals (see: Friends, Seinfeld, Everybody Loves Raymond).

Should they need it, the producers will likely have a little more pocket change at their disposal by the end of the season.

Last week, Touchstone confirmed that Kate Walsh, who plays Dr. Addison Montgomery-Shepherd on the series, could be departing for the show's first spinoff.

A two-hour special episode of Grey's Anatomy, set to air during May sweeps, will act as the de facto pilot for the new, as yet untitled series, allowing ABC time to decide whether or not to pick up the show for its fall season. It's unlikely that any other regular cast members will join the new show, though Taye Diggs and Hector Elizondo have signed on to appear in the pilot.