PEORIA, Ariz. — The Seattle Mariners’ investment in Dustin Ackley already has been huge.

Since drafting him in June with the second overall pick, the Mariners have devoted their best instructors and dozens of hours in one-on-one instruction into Ackley, not to mention the five-year, $7.5 million contract he signed in August.

If there’s one player not named Ichiro or Felix whose future in the organization seems secure, it’s Ackley. Yet, during an offseason of trades, changes and rumors of trades and changes by the Mariners, he learned quickly that nothing is certain in this business.

“I saw guys getting traded in the offseason, and it makes you realize you might not be here for long,” Ackley said last week after a workout at the Mariners’ training facility. “I thought that being drafted this year that it would be less likely they would move me, but you’re always kind of thinking about it.”

If nothing else, Ackley realizes how quickly things can change in the pro game.

Drafted as an outfielder, that’s where he played during the Mariners’ instructional program in September and the Arizona Fall League season with the Peoria Javelinas. In late November, Ackley went home to North Carolina to strengthen his body and be ready for the big-league spring training camp in February.

But the Mariners, with considerable outfield depth but thinner on the infield, had a different idea. They called Ackley back to Peoria for a winter of intense work at second base.

It’s the one position he never played in high school or college, but he was excited when the Mariners told him of their plan. With second baseman Jose Lopez in the final year of his contract, it could be the quickest route to the big leagues for Ackley.

“They wouldn’t do something that wouldn’t be in my or the team’s best interest,” he said. “I knew I would have a great opportunity.”

Since Dec. 2, with a short break for the holidays, Ackley has worked one-on-one with minor league infield coordinator Darrin Garner, often six days a week. They’ve covered smallest details of playing second base, from the double-play pivot to footwork, glove positioning, lateral movement and arm slot on throws.

The Mariners aren’t yet calling it a complete conversion from the outfield, but they want to find out if Ackley can adapt to second base. So far, everyone is pleased.

“He has made tremendous progress,” Garner said. “Since the first day, he showed us that he’s going to be able to make that adjustment as far as catching ground balls. The biggest thing for (him) right now is learning the double-play pivot. As far as catching ground balls, going to his left and going to his right, he’s really improved from the time we started in December.

“He’s all ears and he wants to learn. He applies what you’re teaching and it doesn’t take him long to make adjustments. This kid is going to have a chance to be a pretty good second baseman.”

So far, Ackley says nothing in his work has made him think he can’t pull it off.

“Learning all the little minor details was the biggest thing for me,” he said. “It’s the footwork at second base, where your hands need to be on double plays, where your feet need to be in certain situations, what arm slots to use from different positions. After that, I started to feel more comfortable. I think Darrin has told me just about everything he can teach me. I just need to get better at it and put myself into a position to start spring training.”

Ackley also has been converting his body this winter under James Clifford, the Mariners’ minor league strength and conditioning coordinator. He was a skinny-looking 180 pounds when he signed in August, and say he’s now at 190 with more to gain before the season begins.

Ackley will need strength and stamina to handle a six-month season of daily play as a pro. He learned that during the fall league, even though it was just a 32-game season.

“I got a sense of the grind of season, and that was not that many games,” Ackley said. “There will be 140 games, you’re playing every day and you’re facing all kinds of good pitchers.”

The fall league, when Ackley batted .315 with one homer, 12 RBI and a .412 on-base percentage, helped him believe he can succeed at the pro level, especially as a hitter.

“I guess the fall league can be a little tougher considering guys are coming in throwing only one or two innings as hard as they can,” he said. “I think that definitely prepared me for the wood bat and the atmosphere. I started a little slow, but after getting used to it a little bit I started feeling more comfortable, getting more at-bats and playing on a more regular basis.”

It hasn’t, however, caused Ackley to have a timetable on when he hopes to reach the major leagues.

“Just as soon as I possibly can,” he said. “Hopefully, wherever I start out this year, I can do really good from the beginning and try to prove to people that I can play.”

Read Kirby Arnold’s blog on the Mariners at www.heraldnet.com\marinersblog