"He's got big-time power and has obviously grown and accomplished quite a bit since he's been in Washington," Mariners general manager Jack Zduriencik said. "I was very, very excited today after I talked to him about how excited he was and that really made me feel good."
The Mariners, coming off their third straight last-place finish in the AL West, ranked 27th out of 30 major league teams in runs last season with 619. They were last in slugging and on-base percentage, and 19th in home runs (149).
Looking to help an inept offense and finally attract some hitters, the club is bringing in the fences at spacious Safeco Field next season.
"If you ask me, I feel like I can hit the ball out of the Grand Canyon. The fences are not a problem for me," Morse said.
With the additions of Morse, Morales and reclamation project Jason Bay, the Mariners think they'll have a more dangerous offense.
"It certainly gives you some big pop in this lineup," Zduriencik said. "We were looking for a banger and I think in Michael we got that. ... When you can look around and say you are in position to acquire an everyday guy who can hit the ball hard and hit the ball far, it can change your game. One of the things I have seen since being here is our lack of raw power."
Jaso, a left-handed hitter, had a .394 on-base percentage last season and batted .378 with runners in scoring position. He gives the A's another option at DH and a catching complement for Norris, a right-handed hitter who batted .201 with seven homers in 60 games last year.
Cole, a 21-year-old right-hander, was among four players traded by Washington to Oakland in December 2011 for Gonzalez. Cole was 0-7 with a 7.82 ERA in eight games at Stockton of the California League and 6-3 with a 2.07 ERA at Burlington of the Midwest League, both Class A level.
Baseball America recently rated Cole as the top pitching prospect in Oakland's organization.
Treinen was 7-7 with a 4.37 ERA in 24 games at Stockton last year. The 24-year-old righty was selected by the A's in the seventh round of the 2011 draft.
AP Sports Writers Tim Booth and Mike Fitzpatrick contributed to this report.