His position on the field, though, was always in question - was he a second baseman, an outfielder? - but no one doubted the purity of Ackley's swing. Early in his career, the results followed.
And then Ackley started thinking. And tinkering. And thinking some more. To the point where he couldn't get out of his head standing at the plate. Suddenly the certainty about what Ackley brought wasn't so certain.
''I've told people, I don't care how good your swing is, if you're thinking about stuff, and if you're mind's not 100 percent all in to what you're doing, you're not going to be successful,'' Ackley said. ''That's pretty much a good example of me last year. My swing, it might have been a good swing, but my mind wasn't right, and that's really what screwed me up.''
Now with a new position and a renewed approach, the Mariners are hoping Ackley returns to the hitter he was coming out of college and early in his Seattle career, and less like the tentative, often fiddling hitter he was during 2012 and early last season.
Ackley was widely regarded as the best hitter coming out of college in 2009. It's the reason Seattle didn't hesitate to take him with the No. 2 overall pick after Washington nabbed Stephen Strasburg. His fast rise through the minors and his impressive debut during the 2011 season, when Ackley hit .273 and slugged .417, only reinforced that the pick was the correct one by Seattle.
But instead of building off that first season, Ackley tumbled in 2012. His average slumped to .226. He struck out 124 times. His on-base percentage was under .300. The doubts and the questions started to creep in even while he was standing at the plate. He became concerned with what other comparable players were doing around him, only adding another layer of doubt.
''You see a lot of guys you've played against and this and that and it's like 'I'm a better player than that guy and that guy is playing twice as good as me.' I think that part is frustrating,'' Ackley said. ''I think that's another thing, too, you get caught up in what other guys are doing, you get caught up in this and that and that's another reason why you can't perform at a high level when you're having all these thoughts of this guy and that guy, and my swing and all this.''
The bottom for Ackley came last May 26. In a 13-inning win over Texas, Ackley went 0 for 5. His average stood at .205. Not only was he getting sent to the minors, but his career as a second baseman in the Seattle organization was done and his transition to the outfield started.
''I knew it was probably coming at some point. You can't not perform at this level and expect to stay up there,'' Ackley said. ''Once I got down there I knew it was time to go to work and time to figure stuff out. It really helped me for that second half of the year for sure.''
Thanks to a suggestion from former teammate Raul Ibanez, Ackley began reading parts of the book ''The Mental Game of Baseball.'' Just reading small passages made Ackley realize he needed to get out of his head. So while he was learning to play the outfield at Triple-A Tacoma, he was also rehabilitating his mind.
''It was like the book was reading to me the whole time,'' Ackley said.
When he returned to Seattle late last June, Ackley's mental approach was better and better results followed. Over his final 68 games, Ackley hit .285, looking more like a top prospect and less like a bust.
He'll be learning yet another new position this spring with manager Lloyd McClendon's decision to play Ackley in left field. But what he does at the plate is what will be watched closely through spring and the early part of the season.
''I think most of his struggles were from the mental standpoint than the physical standpoint,'' McClendon said. ''I think he's having fun in camp. ... I think he's enjoying it.''