This article is from the ER FAQ, by Rose Cooper email@example.com with numerous contributions by others.
Sure. In fact, most of them are.
With the exception of Clooney (and, apparently, Bello), all of the
other main cast members had contracts that extended to the 1999-2000
season. Just recently, Anthony Edwards (Dr. Mark Greene) and Noah Wyle
(Dr. John Carter) re-upped through 2001-2002; Edwards, for some Serious
Dough [talk about your new millenium...]. Again, from Jefferson Graham:
"Warner Bros. also plans to cut deals with core cast members [Julianna]
Margulies and [Eriq] La Salle".