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7/26/2013 9:21 P.M. ET

Franklin showing surprising power at second

SEATTLE -- When Mariners rookie Nick Franklin ripped his eighth home run of the season in Thursday's 8-2 win over the Twins, he became just the second American League second baseman in the past 75 years with eight or more homers in the first 50 games of his career.

Franklin hit his eighth home run in his 49th game since being called up from Triple-A Tacoma. Jason Kipnis of the Indians hit 10 home runs in his first 50 games in 2011-12. Prior to Kipnis, the last AL second baseman to do that was Joe Gordon, who hit 11 bombs with the Yankees in his first 50 games in 1938.

"He's up there to hit," said acting Mariners manager Robby Thompson. "And he's not afraid. He jumps on mistakes, which we saw last night. And he's aggressive. He's aggressive in the zone. He's pretty disciplined out of the zone. Every once in a while he'll swing at a changeup, which we all do. Then he regroups and locks back in. He doesn't give away a lot of at-bats."

"That's what we really like about him," said Thompson. "He puts together good quality at-bats each and every ballgame. He's got some pop in there. He hits through the ball. He lets it fly. He's got surprising pop for a little guy. He's strong. He's up there to hit. He's been a very big surprise for us."

Zunino placed on DL, to have surgery

SEATTLE -- Mariners rookie catcher Mike Zunino was placed on the 15-day disabled list Friday and is expected to miss five to six weeks after doctors discovered a broken hamate bone in his left wrist.

Zunino fractured the bone while swinging the bat in the third inning of Thursday's 8-2 victory over the Twins, but remained in the game for another inning before being replaced by veteran Henry Blanco.

Blanco, 41, now becomes the primary backstop. The club signed veteran Humberto Quintero, 33, who was designated for assignment by the Phillies earlier this week. Quintero became a free agent Friday and arrived just in time for Friday night's game.

"We're going to lean on [Blanco] quite a bit from here on out," acting manager Robby Thompson said. "It's too bad because the reason why Hank is here was to mentor Mike and he's done a great job with him. He works with him all the time. He pulls for him every day. Mike is going to miss out on that for these 4-5 weeks, but I'm sure when he's out here, Henry will continue his tutelage with him."

Zunino, 22, has been the Mariners starting catcher since being called up from Triple-A Tacoma on June 12 and was hitting .242 with two home runs and 10 RBIs while helping solidify a position originally occupied this season by Jesus Montero.

Zunino initially thought a foul ball off his wrist had aggravated a previous sore spot, but it turned out he broke the hamate bone on a swing and miss in his second at-bat of Thursday's game. He'll undergo surgery early next week after an MRI exam Friday morning revealed the fracture.

The youngster said this is the first time he'll have to miss significant time in the middle of a season.

"It's frustrating, but it's just another thing you deal with as a player," he said. "It takes nothing away from the team. The team did a great job last night and hopefully they continue to do that. I'm just going to continue to get better as soon as I can to help them out again."

Trainer Rick Griffin said hamate injuries generally require about a six-week recovery, but noted that Ken Griffey Jr. played 23 days after he had surgery on his hamate in 1996.

Zunino was the third overall selection in the 2012 First-Year Player Draft and is regarded as one of the top young catching prospects in baseball. Over his last 11 games, he hit .324 and had the game-winning RBI in each of his last three starts for a Seattle club that has won 10 of its last 11 games.

Montero recently rejoined Tacoma after missing more than a month following surgery on a torn meniscus, but the Mariners have said he'll be limited to first base and designated hitter duties the remainder of the season.

Blanco, 41, has hit .156 in 11 games since being signed by the Mariners on June 14 after the team released Kelly Shoppach.

Jesus Sucre played eight games earlier this year, but remains on the disabled list with a bruised wrist. Thus the Mariners have had a revolving door with their catchers this season, but Thompson said it's part of the game.

"You move forward and continue on," he said. "There's no one that is going to feel sorry for us. That's the way it is. We'll move forward starting today."

Jason Jaramillo, a 30-year-old with some Major League experience, has been the starting catcher for Tacoma the past month, with Brandon Bantz working as his backup. But the Mariners went outside the organization to sign Quintero, an 11-year veteran who hit .250 with two home runs and nine RBIs in 24 games with the Phillies this season.

Quintero will need some time to adapt, but figures to split time quickly with Blanco. He is a career .235 batter who also has played with the Astros, Padres and Royals.

"Once we get him here, we'll sit down as a group and figure that out," Thompson said. "We'll probably split time and do the matchup thing and go from there. One thing about it, Henry does know the pitchers now and has caught most of them. So the next guy we bring in here, we'll pick our spots on how to break him in with our pitching staff."

Ackley starting to heat up at the plate

SEATTLE -- Dustin Ackley has seen a dramatic rise in his batting results since the All-Star break, with the young center fielder hitting .421 in his last six starts going into Friday's game against the Twins.

That's a welcome turnabout for the 2009 first-round Draft pick, who was sent down to Triple-A Tacoma after batting .204 in the first two months. He's hit .270 (17-for-63) with six doubles and nine RBIs since he was recalled on June 25.

"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."

Worth noting

• Michael Morse went 1-for-5 with three strikeouts in his fourth rehab game with Triple-A Tacoma on Thursday and will likely need a few more outings before he rejoins the Mariners, according to acting manager Robby Thompson.

"He got through it fine," Thompson said of Morse's first full game in the outfield. "He just needs more at-bats. He was out six weeks. He has about 12 to 14 at-bats, he needs 10 or 12 more."

Thompson said it's possible Morse will be ready to join the club for the upcoming road trip starting Tuesday in Boston. The big right fielder has been sidelined since June 22 with a strained right quadriceps.

• Top Mariners pitching prospect Taijuan Walker had his first rough outing with Tacoma on Thursday, giving up five runs and six hits with three walks and eight strikeouts in five innings against Tucson. Walker's ERA is now 2.42 after five starts in Triple-A.

• Danny Hultzen, the Mariners other premier pitching prospect, played catch at 60 feet in the outfield under the watch of pitching coach Carl Willis and the training staff on Thursday at Safeco Field as he began working his way back from a shoulder issue that has sidelined him much of the past two months.

Trainer Rick Griffin said Hultzen is working on some slight changes to his motion, with the hope it will alleviate stress that has been causing the problems. There is no timetable on a possible return this season for the 2011 first-round Draft pick.

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.