Ka'aihue signed a one-year deal, which includes a spring training invite, with the Nationals on Sunday, William Ladson of MLB.com reports. Ka'aihue, who spent the last two seasons in Japan, last played in the MLB in 2012, when he appeared in 39 games for the A's. He hit .257/.355/.417 with 40 RBI and 11 home runs in 288 at-bats last season, but he holds just a .221 career major league batting average.