As we get ready for open season on MLB free agents on Tuesday, the Boston Red Sox have announced two roster moves.

Here’s the release:

BOSTON, MA – The Boston Red Sox today announced the following roster moves:

• Infielder Carlos Rivero was claimed off waivers by the Seattle Mariners.

• Infielder Jonathan Herrera was outrighted to Triple-A Pawtucket.

Executive Vice President/General Manager Ben Cherington made the announcements.

Rivero, 26, played in four games (one start) for the Red Sox, making his major league debut and going 4-for-7 (.571) with two doubles, a home run, and three RBI. Before being selected to the major league roster on August 25, he split the season (105 games) between Double-A Portland and Pawtucket, hitting .264 (103-for-390) with 20 doubles, two triples, seven home runs, and 53 RBI.

Herrera, 30, made 42 appearances for Boston in his first year with the organization, hitting .233 (21-for-90) with a double, two triples, and nine RBI. He was optioned to Pawtucket on July 7, playing in 13 games for the PawSox before missing the remainder of the season with a right elbow injury. The switch-hitter will become a minor league free agent this evening at 5:00 p.m. ET.

With today’s moves, Boston’s 40-man roster is now at 36.