Breslow will earn $2.325 million in 2013 and $3.825 million in '14, and the club holds a $4 million option for '15, according to a source.
Breslow was acquired by the Red Sox on July 31 of last season, marking his second stint in the organization.
The 32-year-old Breslow pitched in 63 games last season -- 40 with the D-backs. In his 23 games for Boston, Breslow had a 2.70 ERA. In an example of his consistency, that was the same ERA he had in Arizona.
Breslow graduated in 2002 from Yale University with degrees in molecular biophysics and biochemistry, and was drafted in the 26th round by the Brewers. He has pitched in seven organizations, solidifying his Major League status with three straight years of 60-plus appearances with the A's from 2009-11.
The signing of Breslow meant that the Red Sox have avoided arbitration with all their eligible players.