From 1954 to 1957, Mauch was strictly a player, first for the Los Angeles Angels of the Pacific Coast League, then the Red Sox. His final big-league season, 1957 with Boston, was his most productive. He started 65 games as the Bosox' second baseman and batted a career-high .270 with 60 hits. But the following season, he began his managerial career in earnest. In 1958–59, he piloted the Red Sox' Triple-A affiliate, the Minneapolis Millers, reaching the Junior World Series as American Association champion each season, and winning the 1958 JWS championship.