Mason got his debut with the Tigers then spent the rest of his career in the National League with eight years combined with the Giants, Astros, Pirates, Padres, Phillies and Mets. While an Astro, he pitched in two games and had a 20.25 ERA with no record.

He resurfaced two years later and compiled a 22-35 record with 13 saves and a 4.02 ERA for his career.