Athletics owner, Connie Mack, began a fire sale, and Grove would be dealt to the Boston Red Sox, and initially, it looked like the southpaw was done. In his first year in Boston (1934), Grove only went 8-8 with a horrible 6.50 ERA, and his arm trouble limited him to only 22 Games. He would rebound spectacularly, and while he was not recording the same number of Strikeouts, he was craftier and would win the ERA Title four times for Boston (1935, 1936, 1938 & 1939), and he was first in bWAR for Pitchers three consecutive seasons (1935-37). Grove wasn’t as productive as he was in Philadelphia, but the second half of the 30s still saw Grove as an ace.
Age would catch up to him by 1940, and he retired after 1941. With the Red Sox, he had a record of 105-62.Grove would be chosen for the Baseball Hall of Fame in 1947.