Minor Moves: Watanabe, Poythress, Laffey, Berger

We'll round up today's minor moves here:

• The Red Sox have released reliever Shunsuke Watanabe, who was in camp on a minor league invite, tweets WEEI.com's Alex Speier. The 37-year-old has never pitched in the majors, spending his entire career in Japan with the Chiba Lotte Marines.
• First baseman Rich Poythress has been released by the Mariners, Ryan Divish of the Seattle Times reports (via Twitter). A lifetime member of the Mariners organization, the 26-year-old has never received a big league callup.
• The Nationals signed lefty Aaron Laffey to a minor league deal, tweets Chris Cotillo of MLBDailyDish. Laffey was released by the Orioles earlier this week.
• The A's have acquired left-hander Eric Berger from the Astros in exchange for a player to be named, according to Evan Drellich of the Houston Chronicle (via Twitter). Berger, 27, has never made an appearance in the major leagues.