According to the Globe, Martinez's agent Alan Nero confirmed the news on Monday with the general manager meetings taking place in Chicago. The Red Sox confirmed it a short while later.
After being traded to Boston from Cleveland, Martinez hit .336 with eight home runs and 41 RBIs in 56 games for the Red Sox. He finished the 2009 season with 23 home runs, 108 RBIs and a .303 average in 155 games between the Red Sox and Indians.
Martinez, 30, is in the final year of the five-year deal with a club option for a sixth year that he signed with the Indians in April of 2005.