 On December 5, 1984, as a minor leaguer, he was traded by the New York Yankees with Tim Birtsas, Jay Howell, Stan Javier, and José Rijo to the Oakland Athletics for Rickey Henderson, Bert Bradley, and cash.On June 21, 1989, he was traded by the Oakland Athletics with Greg Cadaret and Luis Polonia to the New York Yankees for Rickey Henderson.Plunk was part of the pennant-winning 1988 Athletics.