CSI and its parent network CBS played hardball Friday by firing two cast members in a contract negotiation dispute.

Longtime cast members George Eads, who played Nick Stokes, and Jorga Fox, who played Sara Sidle, had been with the top-rated show since its debut four years ago. But even that wasn't enough to save their jobs when they decided to try to renegotiate their contracts for a higher salary than the $100,000 per episode they were already getting. Deals with Fox and Eads had already been renegotiated after the first two years and a raise was reportedly offered for this fifth season although there was no contractual obligation to do so. But it seems the offer wasn't good enough for the pair.

According to sources, negotiations had stalled when the two actors had started making veiled threats about not showing up on set as CSI started shooting its fifth season this week. Not showing up for work as a negotiation tactic has worked for a number of actors in recent years, including another CBS star, Brad Garrett of Everybody Loves Raymond.

Fox was sent a termination letter Wednesday, after CBS says they failed to receive a mandated letter from her that she would report to work as scheduled. Eads did comply with the network's request to submit his letter, but reportedly showed up for work extremely late Thursday morning and was sent a similar termination letter soon afterward.

"There comes a point where we feel a contract is a contract," said Leslie Moonves, co-president and co-COO of CBS parent Viacom, to reporters Sunday (July 18) at the TV Critics Association press tour. "We had been having discussions with their lawyers. There were certain veiled threats about their not showing up, and there comes a point where we all have to look out for the future of the network television business."

Moonves went on to add, "we're talking to certain people" about filling the shoes of Eads and Fox on CSI, but no one's been cast yet, and added a "no comment" about the possibility of either actor returning to the series. If recasting doesn't happen quickly, Moonves expects other members of the cast -- he mentions Eric Szmanda (Greg Sanders) and Paul Guilfoyle (Capt. Jim Brass) by name -- to take on larger roles. "CSI has wonderful actors, but if we make a change here and there, I don't think it will hurt the show," Moonves explained.

Meanwhile, production on the fifth season of CSI will stop this week to allow for some rewrites to explain the absence of the two popular characters. It's expected to resume shooting the following week and is on schedule for its season premiere Thursday, Sept. 23 on CBS.