Why the heck was Don Cheadle uncredited in Ocean's Eleven?

Really, you thought that was a good accent? I thought it was one of the worst I ever heard.

I think Mr. Cheadle is one of our finest actors, but the accent nearly ruins a very good movie for me. I saw a preview screening of Ocean’s Eleven, and when I filled out the little card afterwards I begged them to re-dub his lines.