The Mariners, still looking for offensive upgrades, have acquired Washington Nationals outfielder/first baseman Mike Morse in a three-team trade that sent catcher John Jaso to Oakland, while the A’s sent three prospects to Washington.

Morse, who started his career with the Mariners, played in 102 games last year after missing the first two months of the season with a back injury, and hit .291 with 18 home runs and 62 RBI, a .321 on base percentage and .470 slugging percentage. The 30-year-old Morse enjoyed his best season in 2011 when he hit .303 with a .910 on-base plus slugging percentage and hit 31 home runs.

Jaso, who figured to split time behind the plate with Jesus Montero—the only catcher currently on the Mariners’ 40-man roster—hit .276 with 10 home runs and 50 RBIs in 108 games last year.