Playing time was hard to come by for the "spare parts" of the "Big Red Machine." Lum saw far less playing time in Cincinnati than he was used to, as he averaged just 156 plate appearances per season in his three years with the Reds. In , he reached the post-season for the second time in his career. He logged just one at-bat in the 1976 National League Championship Series with the Philadelphia Phillies, flying out in game three to end the seventh inning. He never came to bat in the World Series against the New York Yankees.