With Dustin Ackley continuing to struggle at the plate, the Mariners decided to send him to the minor leagues to "give him the chance to relax, try to clear his head, get back on track."

Dustin Ackley simply ran out of chances to show he can hit big-league pitching.

The Mariners had resisted the urge last year to demote Ackley to Class AAA at the All-Star break, then kept him on the squad this season — stating as recently as last week that he could work through his struggles. But with his average plummeting to .205, mired in an 0-for-24 slump, and seemingly down two strikes in every at-bat over the weekend proved enough to make a move. The Mariners demoted Ackley to AAA Tacoma early Monday and recalled infield prospect Nick Franklin.

“Obviously, we fought for the guy for quite a period of time now,” Mariners manager Eric Wedge said before his team’s game against the San Diego Padres. “We wanted to make it work up here and not have to do that, but ultimately, we didn’t feel like we could take it any further.”

The Mariners took minor-league outfielder Francisco Martinez off the 40-man roster to clear a spot for Franklin. The Mariners also called up pitcher Hector Noesi to work out of the bullpen and optioned left-hander Lucas Luetge to AAA.

Ackley is the second heralded young Mariners big-leaguer to head to Class AAA in the past few days, joining catcher Jesus Montero.

“With Ack, it’s more of a mental approach, a mindset up there,” Wedge said. “It’s not his swing any more. He’s in a pretty good position.”

Mariners general manager Jack Zduriencik echoed that sentiment.

“When you watch his struggles up here, I think it got mental with him,” Zduriencik said. “It became an issue where the confidence, I think, was affecting him. So, give him the chance to relax, try to clear his head, get back on track.”

Franklin entered Monday’s game at second base in the top of the eighth inning and immediately handled a leadoff grounder. He drew a leadoff walk in his only trip to the plate in the bottom of the eighth.

The Mariners will use Franklin primarily at second base in Ackley’s absence. Franklin was drafted in the first round as a shortstop in 2009, but shifted more toward second base at the end of last season in AAA.

“I’ve said this last year, but I feel it’s more of a vacation for me at second,” said Franklin, who hit .324 for Tacoma this season. “Not really, but from short to second, there’s a big difference. Just in the throw, not as much responsibility. So, I’m pretty comfortable with it.”

Geoff Baker: 206-464-8286 or gbaker@seattletimes.com. On Twitter @gbakermariners. Read his daily blog at www.seattletimes.com/Mariners.