Charlie Sheen -- Plea Deal Close

TMZ has learned Charlie Sheen's lawyers are deep in plea negotiations with Aspen prosecutors and a deal is close -- in large part because Charlie's show is hanging in the balance.

Sources close to Sheen tell TMZ Charlie's team has one goal -- the plea deal must be made by May 19 ... the date of the CBS upfronts, when the fall schedule is announced. We're told CBS is skittish about re-upping the show if Charlie's fate is uncertain.

Insiders involved in the contract negotiations tell TMZ it's increasingly looking like Charlie will cut a new deal with Warner Bros. for two more years of "Two and a Half Men."

As for the plea deal, sources say there have been "numerous conversations" between Charlie's lawyers and Aspen prosecutors. As we first reported, the hang-up was over whether Charlie would be pleading guilty to a felony or a misdemeanor.