DETROIT -- The Twins dismissed Triple-A Rochester manager Tom Nieto and hitting coach Floyd Rayford, the club announced Friday.

Nieto, 50, guided the Red Wings to a 102-186 (.354) record over the last two seasons, as the club went 53-91 in 2011 to mark the first time Rochester posted back-to-back 90-loss seasons since 1903-04. Rayford, 54, spent the last two seasons as Rochester's hitting coach, and had been with the organization for the last seven seasons

"The Minnesota Twins organization would like to thank both Tom and Floyd for their contributions," said Twins Minor League director Jim Rantz. "These changes in Rochester are just part of an overall directional change that is being implemented throughout the Minor League system this offseason."

Twins general manager Bill Smith pointed out the changes were made because of Rochester's struggles, and not because of any struggles by young players at the Major League level.

"It's a reaction to the struggles of that club on the field," Smith said. "It's not that some of the guys who come up have had some defensive lapses or baserunning lapses. This is not saying this is their fault. They have to start learning this in rookie ball and adapt and learn the nuances of the game as they come up in the system. It's not just that they didn't learn it in Triple-A."

Twins manager Ron Gardenhire said it was tough hearing the news of the firings, especially considering the fact that Minnesota recalled so many players from Rochester this year, utilizing the disabled list 24 times.

"It's not ever fun," Gardenhire said. "They're good people, and both of them were ex-big league baseball players who had been through lots of ups and downs. As they say, somebody has to take the fall for some rough times through our Minor League system at the top level. We've beat the fire out of them and taken their opportunities because we've been taking all their players. So I feel for Tom and Floyd."

Center fielder Ben Revere, who hit .302 in 32 games with the Red Wings this year, agreed it was difficult hearing about Nieto and Rayford.

"It's tough because you hate to see somebody lose their job," Revere said. "But it's a business. Hopefully they'll find other jobs somewhere else. I wish the best to them."

The Twins also announced the rest of Rochester's staff is expected to return in '12, including pitching coach Bobby Cuellar. The Twins will begin their search process for a new manager and hitting coach immediately.

Additionally, rookie-level Class A Elizabethton pitching coach Jim Shellenback, who also helped instruct players during extended Spring Training in Fort Myers, Fla., is set to retire.

"He's been in the organization for 32 years as a player and coach," Smith said. "He managed a little bit. He's been everywhere. He's always been one of those guys who would do whatever we needed."

Prospect Gibson has Tommy John surgery

DETROIT -- Twins pitching prospect Kyle Gibson underwent successful Tommy John surgery performed by Dr. David Altchek in New York on Wednesday, Twins general manager Bill Smith announced Friday.

Gibson is scheduled to head to Fort Myers, Fla., to rehab for the next year with Minor League rehab coordinator Lanning Tucker, as the recovery time is usually about 12 months.

"It went well," Smith said. "He will start the standard rehab protocol, which is a good thing. There was nothing that came out of the surgery that will make it unusual about the rehab."

Gibson, 23, was officially diagnosed with a flexor pronator muscle strain of the right elbow and a partial tear of the ulnar collateral ligament on Aug. 9. He received a second opinion from Altchek on his injured right elbow in New York on Aug. 22, but was told to finish the initial phase of his rehab before deciding on Sept. 1 to get the surgery.

Gibson was originally placed on the Minor League disabled list with soreness in the flexor muscle area near his elbow, and he underwent an MRI exam on Aug. 3. The 6-foot-5 right-hander is the 33rd-ranked prospect in baseball and No. 2 in the Twins' system, according to MLB.com.

Mauer back at catcher; Nishioka returns

DETROIT -- Joe Mauer started at catcher for the Twins on Friday for the first time since Aug. 20, and Tsuyoshi Nishioka started at shortstop for the first time since Sunday.

Mauer had been bothered by a stiff neck suffered while lunging for a pop fly on Aug. 23, and by an upper respiratory illness that kept him out of two games last weekend. He served as designated hitter the last five games before returning behind the plate on Friday against the Tigers.

Nishioka, meanwhile, has been plagued by a strained right oblique, but said he was healthy enough to make his return against Detroit.

"Even at home, Joe said he could do whatever we wanted, so I could've caught him at home, but we just kind of gave him a few extra days to get over everything he's been going through lately," Twins manager Ron Gardenhire said. "But today I told him that I'd catch him and see where we are tomorrow. Same with Nishi. He needed a few extra days."

Injured starting pitchers Francisco Liriano (left shoulder strain), Scott Baker (right forearm strain) and Brian Duensing (oblique) are also expected to throw bullpen sessions on Sunday. But Duensing -- the only one of the three to make the trip to Detroit -- is the closest to returning and could pitch as early as Tuesday in a relief appearance against the Royals.

"I'd like to get at least one or two starts by the end of the year," said Duensing, who also threw a 40-pitch bullpen session at full strength on Friday. "But that's up to the coaching staff and training staff."