Actor Jeremy Piven, 43, best known for his Emmy-winning role as brash Hollywood agent Ari Gold in HBO's comedy series 'Entourage', has abruptly left cast of 'Speed-the-Plow', the commercial hit Broadway revival of David Mamet's play, after complaining of dizziness, fatigue and difficulty lifting his limbs. Despite being expected to continue in the play till late February, Piven has quit after missing two performances this week.

According to his personal doctor, Piven is an avid sushi eater, eating it regularly twice a day, including taking certain Chinese herbs, a combination leading to extreme mercury toxicity, of which extreme fatigue is a major symptom.

Expressing skepticism at the unusual diagnosis, Mamet sarcastically told Daily Variety: '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.'

Producers of the play say that Piven will be replaced with Norbert Leo Butz, who starred in 'Wicked' and won a Tony for 'Dirty Rotten Scoundrels'from 23rd December - 11th January, while Emmy winner William H. Macy, whose association with Mamet goes way back, will take over the role of a foul-mouthed studio executive on 13th January till the play's scheduled close on 22nd February.