The 36-year-old designated hitter/outfielder batted .274 with 21 home runs and 84 RBIs in 145 games with the Los Angeles Angels last year.
Matsui is a .290 hitter with 161 home runs and 681 RBI over eight seasons, having belted more homers and driven in more runs in Major League Baseball than any other Japanese player.
The two-time All-Star spent his first seven years with the New York Yankees before moving to the Angels last season.
Matsui, who bats left-handed, began his career with Yomiuri Giants of the Japanese Central League and was a .304 hitter with 332 home runs and 889 runs batted in.
Financial terms of the Oakland deal were not announced.
(Writing by Steve Ginsburg in Washington; editing by Mark Lamport-Stokes. To query or comment on this story email email@example.com)
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