Appearing on TV show "Lopez Tonight!" in America on Wednesday, March 9, the "Kangaroo Jack" star said, "Nobody can replace that guy. I did a sketch on the web and it was a joke. We did it last week when all that stuff was funny but I think, this week, it's not so funny anymore."
In the skit, a manic O'Connell kept repeating Sheen's "winning" catchphrase, boasted about his "tiger blood" and at one point pretended to urinate into a plastic cup and drink it as the casting team yelled their disapproval.
O'Connell admitted he now feels bad about shooting the skit, explaining, "Last week...you were watching him and you were like, 'He's funny, he's like that funny uncle...' and now he's like, 'Man, that's that weird uncle that we have'. It's serious."
Sheen has staged a media blitz on TV, radio and online in recent weeks after filming of the current season of the TV sitcom was suspended and then canceled.
Many TV experts have suggested the troubled star is in the early stages of mania and they've urged the actor to seek professional help. Sheen has told Life & Style magazine he fears he's losing his mind.
Meanwhile, Warner Bros. executives have yet to announce a replacement for Sheen on "Two and a Half Men", or even if the show will continue without its star.
In addition to O'Connell, John Stamos and Rob Lowe have also emerged as frontrunners.