This article is from the ER FAQ, by Rose Cooper firstname.lastname@example.org with numerous contributions by others.
Yep. The end of the fifth season will be his last as a regular. For
those one or two Doug/Clooney worshippers out there, there's yet hope: first,
he's not gone yet [repeat after me: "*end* of the fifth season...*end* of the
fifth season..." Now, breathe...good...]; second, he remains on Good Terms
With The Brass, and wants to come back from time to time to maybe, say,
visit with Carol and the quints.
At any rate, the producers don't yet know (or, to probably be more
accurate, still aren't telling) how Doug Ross will be "written out"; again,
in an interview with Jefferson Graham of "USA TODAY", when he asked Lydia
Woodward directly about the issue, she said they "haven't decided" how they'll
write Clooney out of the show, but "we are talking about it". And what of
last year's rumor about "ending with a bang"? "'I would seriously doubt it,'
she says. 'But I would hesitate to rule anything out.'"
And The Man Hissef? Oh, I think he'll be Alright. Call it a hunch.
His production company has a deal with CBS (originally with NBC) to develop
pilots. Plus, he's been in a movie or two...but do I hear someone out
there moaning, "well, so was Caruso"? Hmmm...time will tell...