Caleb Durbin, who was acquired in a trade with the Brewers just before spring training, will be the starting third baseman for the Red Sox on Opening Day.
The Red Sox had a vacancy at the position after free agent Alex Bregman signed with the Chicago Cubs during the offseason, and Durbin, 25, has been sharing time at third base with Marcelo Mayer this spring
Source: Caleb Durbin to start at third base for Red Sox on Opening Day – ESPN