Why is Rob Lowe really leaving his role as The West Wing's Sam Seaborn in March? "It's entirely a money situation, I assure you," says creator Aaron Sorkin. "It has nothing to do with anything else."

As Sorkin explains it, WW's pilot was "expensive to make" and the producers didn't know it'd be a hit from the outset. So Lowe and co-stars Allison Janney, Richard Schiff, John Spencer and Bradley Whitford were asked to "significantly reduce their [salary] quote" to be in the series. "[They] did, Rob did not," he says. "Nobody's the villain. It's a business situation."

Last season, Lowe's castmates reportedly were raised from $30,000 per episode to his $70,000 level, while he was refused a payhike. Says Sorkin: "While it's possible to say, 'Everybody else on the show got a raise except for Rob and that's not fair'... the fact of the matter is Rob had his raise two years longer than everybody else."

That said, Sorkin praises Lowe's performances as President Bartlet's speechwriter, adding: "I just want to be clear. There's nobody at NBC, nobody at Warner Bros. and nobody on the show that wants Rob to leave. Sam Seaborn isn't going to die, so the door is always gonna be open. The chances of Rob staying? I talk to Rob every day and everybody wants him to keep doing the show. He's really very good and comes to work enthusiastically.