John Joseph Mizerock (/ˈmɪzərɒk/; born December 8, 1960) is a former Major League Baseball backup catcher for the Houston Astros and the Atlanta Braves. He was the eighth overall pick in the 1979 Major League Baseball Draft. He later served as a coach for the Kansas City Royals and Philadelphia Phillies. He is currently the hitting coach for the Clearwater Threshers.