The Red Sox started the week by adding some much-needed pop at first base with the signing of free agent first baseman Nathaniel Lowe, who was immediately added to the roster.

League sources said late Sunday night that the club was close to finalizing a contract with Nathaniel Lowe, whom they hope will provide a boost at first base, specifically against righthanded hitters.

The Red Sox have struggled to find a consistent option at first base this season, and Lowe could operate as the strong side option of a platoon with Romy Gonzalez at the position, handing the startin...