The Pulitzer-winning playwright (Between Riverside and Crazy, The MF with the Hat, The Last Days of Judas Iscariot) began his career as an actor, and old colleagues still want to work with him. But until this summer, he hadn’t been onstage since 2004, and in the meantime he’d let stress affect his health in other ways and backed out of several acting jobs he’d already accepted. As the time approached for the revival of Mamet’s American Buffalo he’s now co-starring in, his body brought things to a crisis.