"Entourage" star Jeremy Piven is citing health problems for a change in plans regarding his Broadway show.

"We have been advised by Jeremy Piven's medical representatives that he is seriously ill and is unable to fulfill his contractual obligation to 'Speed-the-Plow.' Consequently, he has left the production ten weeks early," the play's producers said in a statement.

Tony Award winner Norbert Leo Butz will take over Piven's role of Bobby Gould in the movie industry satire from Dec. 23 through Jan. 11, followed by William H. Macy, who will assume the role from Jan. 13 through Feb. 22, the statement said.

Piven recently informed the producers that he has not been feeling well due to a condition attributable to a high mercury count, Variety reported on Thursday.

Variety quoted David Mamet, the writer of the play, as saying of Piven's departure: "I talked to Jeremy on the phone, and he told me that he discovered that he had a very high level of mercury. So my understanding is that he is leaving show business to pursue a career as a thermometer," Mamet said.