peacock entered the majors in 1937 with the boston red sox, playing for them through the 1944 midseason before joining the philadelphia phillies (1944–1945) and brooklyn dodgers (1945). in his rookie season, he hit a .313 batting average in nine games played. the next eight years he averaged 76.25 games in each season, with a career-high 92 games in 1939. his most productive years came with boston, when he hit .303 with a career-high 39 rbi in 1938, and .284 with 20 doubles in 1944.