After hitting just .205 and being sent down to Triple-A Tacoma in the first half of the season, Ackley hit a team-leading .304 with a .374 on-base percentage and .435 slugging percentage after the All-Star break to quiet critics who wondered if he'd ever develop into a key cog in Seattle's offensive attack, as was envisioned when he was selected with the second pick in '09.
While it's fair to ponder whether Ackley will wind up back at second base or continue working in the outfield when a new manager takes over next season, it seems far more certain now that he remains part of the plan.
An August surge, when Ackley hit .390, did wonders for the 25-year-old's mental approach heading into the offseason.
"September wasn't as great, but that month I had put me in a position mentally to know it's there, that it's just a mental thing and I just have to get up there and attack every at-bat and not be tentative in any way," Ackley said. "When I did that, I had the most success, and it felt like it used to. Before, when I had times when my average was going up, I didn't really trust it because it didn't feel the way it did in the past. This time around, it finally felt like I could hit anything at any time ... righty, lefty, whatever.
"That's the confidence I needed to realize it's in there and this is what I needed to do and that's the biggest thing for me going into the offseason."
Ackley has returned to his winter home in Lapeer, Mich., a small town about 50 miles north of Detroit, where he'll work out over the coming months in an expanded hitting cage and workout facility he's installed in a barn on his property.
"I would like to get a lot stronger going into next year, just physically as far as running and having more power in the box," Ackley said. "Just little things. It'll be a good offseason to get after it."
Ackley came into pro ball with a natural swing and batting eye that seemingly made him a slump-proof hitting prospect. He'd flat-out hit at every level he'd ever played and quickly climbed through the Mariners system to a midseason debut in 2011, when he hit .273/.348/.417 in 90 games and finished sixth in the American League Rookie of the Year voting, despite only playing three and a half months.
But things didn't go nearly as smoothly in a .226/.294/.328 sophomore campaign and Ackley was sent back to the Minors this past June after a rugged start left him battling the Mendoza Line for the first several months.
When Ackley came back, he found himself playing center field, after rookie Nick Franklin had grabbed hold of the second base job. But instead of doubting, Ackley dug in. And for some reason, he started hitting again.
The reason, in Ackley's mind, was mostly in his head.
"If your mental side is there, odds are the physical is going to be there," Ackley said. "But it doesn't necessarily work the other way around. I'm a big believer in that now. If you're not mentally there 100 percent, then it doesn't matter if you have the best swing in the world. You're not going to succeed at this level. If you have any thoughts other than going up there and crushing the ball or seeing the ball or whatever, then you're in trouble."
And that is one lesson Ackley had never learned -- and never needed to learn -- as he was excelling at every previous level of baseball.
"It's not like you practice, 'Oh, I'm going to screw my head up mentally and then try to work out of it,'" he said. "You just go through those spurts where you're struggling and you get into your own head and you just have to work your way out of it. For me, I'm glad that I've been through it and know what to do and how to not panic. This year was good for me that way. It was a rough year, but overall I think it was a pretty good one for me, career-wise."
As for going forward? Ackley started 54 games in the outfield last season and 49 at second base. He gained confidence defensively at the same time his offense began coming around, giving the Mariners a competent center field option with Franklin Gutierrez's contract expiring.
Former manager Eric Wedge felt Ackley's versatility could be a desirable weapon, comparing him to Tampa Bay's Ben Zobrist. From Ackley's perspective, he'll play wherever needed. The only difference will be spending more time strengthening his throwing arm in the offseason, in anticipation of playing more center field.
"I thought it'd be way tougher than it was," Ackley said of the outfield transition. "It's definitely not easy flip-flopping and not knowing where you'll be, but I've worked at a lot of those positions in college and the last several years now in the pros. To me, if I'm just able to stay sharp and do the little things in BP and infields and stuff, there's no reason I can't be sharp at all those positions at any point.
"Even going back to second after a couple months, it felt just like it did before. I don't see any problem with it. If that's what they want me to do, I'm sure it'll help me get in the lineup more."
If Ackley performs like he did in the second half, the Mariners will find a place for him to play. He remains one of the club's best athletes. Now he just needs to remember that himself.
"The better my hitting was, the better my defense got," Ackley said of his second half. "I don't know if that's because my confidence was getting higher or what, but it seemed like the more mentally I was there on hitting, the more it was there in the field, too. And that makes sense. Everything is better when you feel good."