MINNEAPOLIS -- The Twins have commended left-hander Glen Perkins this season for the strides he's made in terms of his preparation and his overall growth as a pitcher.

But there is still one area where both Perkins and Minnesota's coaching staff feel he could improve, and that's his ability to shake it off when a close pitch call doesn't go his way.

Perkins issued a career-high four walks in 5 1/3 innings against the Tigers on Wednesday night, and pitching coach Rick Anderson said that the control problems began after Perkins didn't get the call on some pitches that were right around the strike zone.

"He then tried to make a better pitch and then a better pitch, and the next thing you know, it's ball four and he's fuming at himself," Anderson said. "That's the mental part. An umpire is going to miss a pitch, and they are going to give you pitches. That's just part of the game. It's up to you to keep your mind-set and under control."

Perkins didn't factor into Wednesday's 14-10 walk-off win. But it was some struggles by the starter, allowing five runs on five hits, which erased what had been an early 3-0 lead for the club.

Three of the four walks that Perkins issued eventually led to runs. In the fourth inning, Perkins walked the bases loaded -- issuing a one-out free pass to Miguel Cabrera before handing out back-to-back two-out walks to Jeff Larish and Brandon Inge. Adam Everett then hit a two-run single to center, pulling the Tigers within one run.

"I had a couple close pitches to Cabrera there and then I kind of lost focus of what I needed to do," said Perkins. "When you walk the bases loaded like that, things are going to happen. I think it was a combination of trying to make better pitches and instead I started to get the ball up.

"I'm not worried about it [moving forward]. I know I'm not that kind of pitcher. I'm not the kind of guy that's going to walk four guys in five innings, or walk four guys in any game. ... It's my responsibility to take a step back in those situations and take a deep breath and refocus and make pitches."

While Wednesday night was the first time that walks proved costly for Perkins, it was a continuation of some poor outings for the starter. The left-hander has not delivered a quality start over his past four times on the mound. He's allowed at least four runs and has been unable to pitch past the sixth in each of those starts. The troubles have come after he delivered three straight eight-inning outings to start the year, allowing two runs or less in each.

"I think I need to get back to focusing on throwing the ball down in the zone and moving the ball in and out," said Perkins, who has an ERA of 7.25 over his past four starts. "I think maybe these last couple starts, I've started to throw more than pitch. That's never a good thing.

"But I know what I'm capable of doing. I did it for the first three starts of the season and all of Spring Training. I need to get back to making them try to hit my pitches. I think right now it's a mental thing and something I need to focus on doing rather than just thinking it's going to happen."

Anderson said it's that change in focus which could help Perkins get back to pitching like he did early in the year.

"The biggest thing with Perk is himself, not the other team," Anderson said. "He's doing many of the right things -- trying not to overthrow and to change speeds and do the things you are supposed to do -- as you saw for the first three outings. But the other thing he has to do is not worry about things he can't control. If he can get on track with the mental part, he'll be fine."