A matsayin Phillie, Johnstone ya tafi 7-for-9 a cikin
1976 National League Championship Series (NLCS), a kan Cincinnati Reds; duk da haka, Reds ya shafe jerin. An tura shi da Bobby Brown daga Phillies zuwa Yankees don Rawly Eastwick a ranar kafin ranar ƙarshe na ciniki a ranar 14 ga Yuni, 1978.