The Mariners' converted second baseman made a diving catch off a hard grounder headed into right field and turned it into a forceout at second during an intrasquad game at the Peoria Sports Complex.
A shortstop in high school and outfielder and first baseman in college, Ackley was selected second overall in last June's First-Year Player Draft as an outfielder. But the Mariners decided after the Arizona Fall League to give him a go at second base.
He returned to Arizona from his North Carolina home in early January for a crash course on the position and has done better than even he expected.
"I didn't know what it would be like playing second, turning double plays and things like that," he said on Monday, "but it has been going really well. I'm glad I was able to come out here during the offseason and get all that time taking ground balls. I think that helped a lot."
The conversion reached another stage during the intrasquad game.
"I only got one ground ball over there," he said, "but it was good to see balls come off the bat live."
Ackley said he was hoping that the first ball hit his way was not directly at him.
"The ones right at ya might get ya," he said.
Mariners infield coach Mike Brumley said he has been impressed with what he has seen from Ackley so far this Spring Training.
"He has really come along well," the first-year coach said. "A lot of guys in our Minor League system have spent a lot of time with him and they have done such a good job that it looks like he fits there."
Ackley figures to see plenty of action during the early stages of the Cactus League, which begins Wednesday afternoon against the Giants at Peoria Stadium. He eventually will be re-assigned to the Minor League camp, which starts on March 12.
"He's very athletic, quick, a smooth-type player," Brumley said, "so maybe he doesn't look as quick as he really is. It's kind of like hitting. He has such a smooth transition in anything he does. He has great timing with his body.
Now, it's a matter of game experience. It is very encouraging and he is going to be a joy to watch."
Ackley also contributed a double to the Mariners' No. 1 team's 5-2 win over Mariners No. 2.
"I thought Ackley really swung the bat," manager Don Wakamatsu said. "You just see the athleticism. This guy hasn't played much professional baseball, but he sure looks polished."
Right-hander Ian Snell was the first of nine pitchers that held the No. 2 team to four hits -- two of them off right-hander Steve Shell, who surrendered both runs.
"I thought Snell looked really good," Wakamatsu said. "He looked stronger, more confident, under control."
Snell, acquired from the Pirates just before the July 31 non-waiver Trade Deadline, could emerge as the No. 3 starter.
Jim Street is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.