As a member of the pennant-winning 1975 Red Sox, he was the starting pitcher in Game 2 of the 1975 American League Championship Series against the Oakland Athletics. He allowed three runs and seven hits in five innings of work, exiting the game with the score tied, 3–3. He earned a no-decision, with Red Sox relief pitcher Roger Moret gaining credit for the win when Boston prevailed, 6–3. Then, in the 1975 World Series, Cleveland worked in three games, two in relief. He was the starting pitcher in Game 5 against the Cincinnati Reds on October 16 at Riverfront Stadium. He gave up seven hits and five runs, all earned, and was charged with the 6–2 loss. He also came out of the bullpen in the top of the ninth inning of Game 7 at Fenway Park and got the final out, but the Reds had already forged ahead against Cleveland's predecessor on the mound, Jim Burton, and secured a 4–3 win and the world championship. The 1975 campaign afforded Cleveland his only postseason appearances; in his four games and 11 innings pitched, he compiled a 0–1 win–loss record and a 6.17 earned run average.