Dec. 18 (Bloomberg) -- A beleaguered Broadway season lost one of its stars yesterday, as “Entourage” actor Jeremy Piven unexpectedly quit a revival of David Mamet’s “Speed the Plow” two months before the show’s scheduled closing.

Samantha Mast, a Los Angeles-based spokeswoman for Piven, said that the 43-year-old actor wasn’t “feeling well” and was advised by doctors to end the run immediately. She referred further questions to Dr. Carlon M. Colker, chief executive of Peak Wellness of Beverly Hills, California and Greenwich, Connecticut, which according to its Web site is a leader in the “health and wellness community.”

“He was feeling an inordinate amount of exhaustion,” said Colker, a former competitive body builder and contributing editor to Muscular Development Magazine. “It was really my decision.” for him to quit the run before his contract expired, on Feb. 22.

Colker, 43, said Piven had the highest levels of mercury in his blood Colker has seen. Studies suggest high mercury can lead to increased risk of heart disease or neurological problems. He said Piven was eating sushi twice a day, a source of mercury. Piven was hospitalized for three days, Colker said, but declined to name the hospital.

Piven played a cynical movie producer, opposite Elisabeth Moss, a wily assistant, and Raul Esparza, another producer. Norbert Leo Butz will replace Piven beginning on Dec. 23 and William H. Macy will replace Butz on Jan. 13, according to a statement from the show’s producers. Piven’s understudy, Jordan Lage, assumes the rule through Dec. 21.

A producer of the show who spoke on condition of anonymity said he’s hopeful it will recoup its roughly $3 million capitalization this month, and called Piven’s explanation “fishy.”

Mamet was also skeptical.

“I talked to Jeremy on the phone, and he told me that he discovered that he had a very high level of mercury,” Mamet told Variety. “So my understanding is that he is leaving the show to pursue a career as a thermometer.”

Colker responded: “I think it’s profoundly insensitive and reflects a complete lack of understanding about the medical condition.”

Colker said high living wasn’t behind Piven’s exit.

“For whatever ‘partying’ he was doing, he was just trying to live his life,” Colker said. “If anything he was doing far less than he usually does.”

To contact the writer on this story: Philip Boroff in New York at pboroff@bloomberg.net.

Last Updated: December 18, 2008 14:04 EST