During his career, Pappas was in the top 10 in ERA eight seasons, in wins six seasons, fewest walks per nine innings nine seasons, complete games seven seasons, shutouts eight seasons, and he was tied for the league lead with a perfect fielding percentage (1.000) in four seasons. Only posting a career .123 batting average, Pappas hit 20 home runs as a pitcher; as of 2020, he is one of 13 pitchers to hit at least 20 home runs. On August 27, 1961, while with the Orioles, Pappas pitched a two-hit, 3–0 shutout against the Minnesota Twins at Metropolitan Stadium and helped his own cause by homering twice off Pedro Ramos. Pappas also homered off Bill Stafford in the Orioles' 1–0 victory over the New York Yankees on April 18, 1962; he was the last American League pitcher in the pre-designated hitter era to hit a home run in a 1–0 game. Not until Nathan Karns in would another American League pitcher accomplish this feat.