"I've just continued to work in the cage and continued to get my confidence where it needs to be," Ackley said. "I'm going up there with the mentality that I'm going to get a hit every time and that's really what separates me now from me before."
Acting manager Robby Thompson said that approach is critical for any player.
"I think it's probably more mental than anything," he said of the improvement. "I think he's been a little more aggressive in the zone early in the count. We all saw before that it seemed like every time he stepped in the box he was 0-2. It's hard to hit anywhere 0-2, let alone at the big league level.
"I think he's picking his spots when to let it go. A great example was last night when the lefty came in. He was ready for that first pitch and smoked a double into right-center field. We hadn't seen that. It's a good sign from Ack. He's more confident up there and confidence plays a big role in this."
Ackley, 25, is also getting comfortable in his new role in center field, where he's been playing since his recall now that Nick Franklin has taken over at second base.
"For sure, I'm just getting better reads on the ball," Ackley said. "[Outfield coach Mike] Brumley is unbelievable how to shade guys and that. You can see that for sure. But yeah, I feel great going after balls. I think the more balls I get, the better it's going to be."
Greg Johns is a reporter for MLB.com. Follow him on Twitter @GregJohnsMLB as well as his Mariners Musings blog. This story was not subject to the approval of Major League Baseball or its clubs.