On August 25, 2017, Moreland made the second pitching appearance of his career, tossing an inning against the Baltimore Orioles in a 16–3 Red Sox loss; he allowed two hits but no runs, striking out one batter, catcher Caleb Joseph.
During the regular season, Moreland played in 149 games, primarily as Boston's first baseman, batting .246 with 22 home runs and 79 RBIs.

In the postseason, Moreland played in all four games of the ALDS, batting 5-for-13 (.385) as the Red Sox lost to the eventual 2017 World Series champions, the Houston Astros.
On December 18, 2017, Moreland signed a two-year contract with the Red Sox.
On August 25, 2017, Moreland made the second pitching appearance of his career, tossing an inning against the Baltimore Orioles in a 16–3 Red Sox loss; he allowed two hits but no runs, striking out one batter, catcher Caleb Joseph. During the regular season, Moreland played in 149 games, primarily as Boston's first baseman, batting .246 with 22 home runs and 79 RBIs.
In the postseason, Moreland played in all four games of the ALDS, batting 5-for-13 (.385) as the Red Sox lost to the eventual 2017 World Series champions, the Houston Astros. On December 18, 2017, Moreland signed a two-year contract with the Red Sox.
Mitch Moreland