OAKLAND _ The Oakland A's today announced several roster moves to set their 25-man roster for the season opener against Boston Tuesday in Tokyo, Japan.

The A's have selected designated hitter Mike Sweeney from Triple-A Sacramento and added him to the roster. To clear a spot on the 40-man roster, the A's have placed right-handed pitcher Kiko Calero on the 60-day disabled list with a torn right rotator cuff.

The A's also placed third baseman Eric Chavez and right-handed pitcher Chad Gaudin on the 15-day disabled list retroactive to March 19. Chavez is rehabbing from off-season back surgery and Gaudin is rehabbing from off-season surgery on his left hip.

The A's also optioned infielder Gregorio Petit to Sacramento to reduce their active 40-man roster to 28 players. The A's have also designated pitchers Justin Duchscherer and Dana Eveland and outfielder Carlos Gonzalez as inactive for the two games against Boston in Japan. The A's must reduce their active 40-man roster to 25 players by March 30.