A rep for the former "21 Jump Street" actor tells us that Grieco's team is "actively pitching Richard to WB and Chuck Lorre to take over now that Charlie's gone."
We're told Grieco feels he's perfect for the role because he has a lot in common with Sheen's character ... including the fact they both let their siblings stay with them after a divorce.
Grieco's people also point out he doesn't have any substance abuse issues ... and insists he would be a reliable employee.
Stay tuned ...