EXCLUSIVE: CAA has signed William Petersen, who’s ready to get busy again almost five years after leaving the CBS drama CSI after 10 seasons. He will be looking at movie, TV and stage opportunities. Petersen emerged from the Chicago theater scene to star in such films as William Friedkin’s To Live And Die In L.A. and Michael Mann’s Manhunter and is one of those highly selective actors who never wore out his welcome — which made a return seamless when he surprised everyone by signing on for CSI, on which he remains an exec producer. Petersen had been repped by WME for the past year. A founder of Chicago’s Remains Theater Ensemble, Peterson’s recent stage work includes A Dublin Carol and The Endgame at Steppenwolf Theatre and Blackbird at Victory Gardens Theater in Chicago. He continues to be managed by Cindy Chvatal at High Horse Films and is lawyered by Cliff Gilbert-Lurie at Ziffren Brittenham.