Is Charlie Sheen going from porn to politics?

Sheen, who stars in Showtime's upcoming movie Rated X, about porn kings Artie and Jim Mitchell, may possibly be stepping into the mayor's office. Not for real, of course, but in the political sitcom Spin City.

According to E! Online columnist Ted Casablanca, Sheen is being considered to replace the ailing Michael J. Fox, who announced he was leaving the ABC sitcom at season's end due to Parkinson's disease.

Sheen's rep referred calls to DreamWorks Television, which coproduces the political satire starring Fox as the deputy mayor of New York City. The production company had no comment.

An ABC spokesperson says no decisions have been made about the future of the show, which has earned Fox a case-full of awards including three Golden Globes and a People's Choice trophy.

Sources close to the show say there's no decision yet even how to conclude this season, let alone approach next year. Will the show focus around Heather Locklear, who joined the cast this season as the mayor's campaign manager? Will the show end and cast members move to a spinoff? Will a new star be hired to fill Fox's job? Will Fox appear in some of next season's episodes to smooth the transition to a new star?

The Sheen scenario seems possible (if not probable), considering the oft-troubled actor starred in Sugar Hill, a 1999 DreamWorks pilot for ABC, produced by Spin City creator Gary David Goldberg. The pilot was not picked up and Goldberg restructured it, without Sheen. (It's now Battery Park, premiering tomorrow on NBC.)

Last month the popular, family-oriented Fox, made the surprise announcement that he would not return for a fifth season of Spin City because he feels his "time and energy would be better spent with my family and working toward a cure for Parkinson's disease."

On and off screen Sheen is a sharp contrast to squeaky clean Fox. Once an A-list actor, the Hot Shots star is now better known for his sordid personal life. In 1987 he was the lead in Wall Street, but, by 1990, he was in rehab, in 1995 his name showed up in Hollywood madam Heidi Fleiss's little black book, he was busted several times, he overdosed, and, by 1998, he was on probation wearing an ankle bracelet.