The actor quit the Broadway show less than two months into the production and left producers to scramble around and find a replacement. William H. Macy signed up at short notice.
Piven maintains a bout of mercury poisoning cost him the role of a lifetime - and he wasn't faking it.
He tells the Los Angeles Times newspaper, "That talk really did hurt. I grew up in a family that dedicated its life to the theatre... There was this misconception that the Hollywood boy tried to do Broadway not realising what it was. Doing Mamet on Broadway is the Holy Grail (for an actor). If anyone thinks I would take something like that for granted, they've got the wrong guy.
"My body was literally trying to survive. I was in bed every day until the moment I hit the stage. As soon as I was offstage, I was in bed."
Piven's only regret is that he didn't fire back at the criticism at the time: "I didn't retaliate, decided to take the high road. Now I think I did the wrong thing in doing that."
The poisoning turned into the Epstein-Barr virus and floored Piven for weeks. He admits the illness was a wake-up call.
He explains, "I'm dedicated to my health and to getting into the best shape of my life."