On Opening Day 2015 on April 6, in his first game with Boston in almost 10 years, Ramírez played left field for the first time in his career and hit two home runs (one being a broken-bat grand slam) for a total of 5 RBI as the Red Sox routed the Philadelphia Phillies 8–0.
On April 29, Ramírez hit his 10th home run of the season, joining teammate David Ortiz as the only players in Red Sox history to hit 10 home runs in the month of April.
However, a few days later on May 4, Ramírez left the game against the Tampa Bay Rays in the top of the first inning after crashing into the left field wall at Fenway Park.
The team announced shortly after that he had suffered a left shoulder sprain.

Ramírez ended the 2015 season with a .249 batting average and 19 home runs in 401 at-bats, as his defensive rating in left field was rated as the worst in the American League.
As a result, on September 1 the Red Sox announced Ramírez would not play left field for the remainder of the season.
The Red Sox also announced then that Ramírez would again change positions in 2016, as its starting first baseman,  a new position that he never played before.
On Opening Day 2015 on April 6, in his first game with Boston in almost 10 years, Ramírez played left field for the first time in his career and hit two home runs (one being a broken-bat grand slam) for a total of 5 RBI as the Red Sox routed the Philadelphia Phillies 8–0. On April 29, Ramírez hit his 10th home run of the season, joining teammate David Ortiz as the only players in Red Sox history to hit 10 home runs in the month of April. However, a few days later on May 4, Ramírez left the game against the Tampa Bay Rays in the top of the first inning after crashing into the left field wall at Fenway Park. The team announced shortly after that he had suffered a left shoulder sprain.
Ramírez ended the 2015 season with a .249 batting average and 19 home runs in 401 at-bats, as his defensive rating in left field was rated as the worst in the American League. As a result, on September 1 the Red Sox announced Ramírez would not play left field for the remainder of the season. The Red Sox also announced then that Ramírez would again change positions in 2016, as its starting first baseman,  a new position that he never played before.
Hanley Ramírez