When Scott Diamond gave up six runs or more in three of his last five starts in July and August, everyone agreed he needed some time at Class AAA Rochester to work out his problems. Ron Gardenhire agreed. Terry Ryan agreed. Even Scott Diamond agreed.

“I had started overcomplicating things, putting a lot of pressure on myself. Just trying to make that perfect pitch every time,” the Twins’ 2012 pitcher of the year said. “It’s just not who I am, it’s not the way I pitch. Going down there helped me realize that.”

Yes, pressure often is a destructive force, even for a Diamond. After a 12-9 breakthrough last year, he is just 5-10 with a 5.52 ERA in 20 big-league starts this year.

But with the burden of expectations relaxed, and the tension of a minor league pennant race growing last month, Diamond excelled. He made six starts for Rochester, and the Red Wings won five of them (with a bullpen collapse responsible for the lone loss). His ERA was 2.40, opposing batters hit only .217, and the biggest success was in his own mind.

“Confidence was the big thing when we sent him down, and he’s definitely confident right now,” Gardenhire said. “He knew his pitches weren’t finishing. … He had some success, and kind of took off from there. He pitched very well down the stretch. At least we know he’s got his confidence back, and that’s huge.”

The Twins are demonstrating their own faith in him, too, bringing him back for September and putting him on the mound. They are even creating a six-man rotation, at least for the moment, to give him the chance. He will start against Oakland on Thursday and will get another opportunity on next week’s road trip.

“At the time we sent Scott out, it was the right thing to do for both of us. The year he had last year, our expectations were up,” said Ryan, the Twins general manager. “Once we got into the midsummer, we didn’t see the crispness and location. … I’m hoping now that he’s back, we can see some of what we saw last year.”

So does Diamond, who can re-establish himself as a mainstay in next year’s rotation with a strong September. “But at the same time, I’m also pitching to show to myself that I can still play in this league,” Diamond said. “I’m feeling really confident coming in. I’m eager to get back out there.”

Mauer stays inside

After a couple of days of outdoor workouts and baserunning drills, Joe Mauer stayed indoors Tuesday as he works his way back from an Aug. 19 concussion. But it wasn’t a setback, Ryan emphasized.

“It was trainer’s choice. We wanted to give him a day off, basically,” Ryan said. “We’ll get him back outside” on Wednesday.

The team has not set any goals for the All-Star catcher’s return, but the GM didn’t dismiss the notion that Mauer could return to action during this homestand, which concludes Sunday.

“I don’t know what the timetable is going to be, but I’m hopeful,” Ryan said. “That would be great.”

Rising rookie

Oswaldo Arcia had not homered since Aug. 10, but when the right fielder smacked a Jarrod Parker pitch into the upper deck in the sixth inning Tuesday, he resumed his pursuit of the top rookie home-run hitters in Twins history.

With 11 homers, Arcia won’t reach Jimmie Hall, the franchise rookie record-holder, who hit 33 in 1963, or Marty Cordova’s 24 in his American League Rookie of the Year season in 1995. But Arcia, currently sixth, has a shot to catch Dan Ford (15, 1975), Bernie Allen (12, 1962) and Dustin Mohr (12, 2002).