By just about any measure, the Twins offense has slipped this year. There have been a handful more home runs and doubles, but the batting average is down nearly 20 points and the on-base percentage by a dozen; they will score about 80 fewer runs; and the strikeouts have exploded.

Amid the carnage of another 90-loss season, hitting coach Tom Brunansky is as frustrated as his pupils.

“My whole goal was to try to expedite the [maturation] process, to make sure our hitters are more major league-ready at the end of the year than they were at the beginning,” the 53-year-old former Twins slugger said. “A few have reached that goal, but not as many as I’d hoped. That’s what’s so disappointing.”

Brunansky, who spent the three previous seasons working with Twins minor leaguers, knew when he was promoted to the majors last winter that he would be working with many of those same players, as the franchise tried to transition to a younger roster. The challenge, he said, was to get hitters to believe they belonged.

“It’s important that they reach a confidence level so that when they go to the plate, they’re playing the game. They’re not thinking, ‘I need this hit to prove I belong here, that I should stay in the big leagues,’ ” Brunansky said. “My goal is to get them to accept that, if they just try to help the team, not do it for themselves, their worth will be evident. That’s how you win. But it’s so hard for young guys to believe that. That’s what I see down the road.”

He hopes to be back next year and says he has enjoyed the challenge, but he admits to being uncertain about his future. “It’s there,” he says of the year-end anxiety. “You can’t walk away from that. With us, it’s all one-year contracts. I knew that coming in — when you reach this level, it’s about won-loss, and showing improvement.”

That’s why the incredible barrage of strikeouts is so bothersome. The Twins eclipsed the franchise record of strikeouts in a season before Labor Day, and their total of 1,391 entering the weekend — the fifth-most in major league history — is already 300 beyond last year’s total.

“We’ve got way too many guys striking out way too often. We’ve got to fix that,” General Manager Terry Ryan said. “And I think we can. We’ve got to have a different mind-set, maybe, with two strikes. We’ve got to jump on the first-pitch fastball more often.”

Are the strikeouts a reflection of the hitting coach? To some extent, yes, Ryan said: “No one’s hiding from that. It’s been a transitional year for a lot of things, and that’s one of them — a new hitting coach.”

Brunansky has been tireless in working with Twins hitters, doing individual coaching in the batting cages nearly every day. But the strikeouts won’t stop.

“It’s really frustrating because they come in situations where they shouldn’t happen. You can’t [eliminate] strikeouts, we understand that, but there are situations where we have to compete. If we’ve got a runner on third base, we can’t take a fastball on the outer edge of the plate.”

He hasn’t accomplished what he had hoped, not even close; only a few hitters have improved, though Brunansky said he has made progress in winning his pupils’ trust.

And he is optimistic things will be better next year, in part because of all the failure the Twins have experienced this season. “You almost have to give young players at-bats to fail, before you can reach them,” Brunansky said. “Guys come up thinking, ‘Hey, I was doing well at Triple-A,’ so how do you get them to adjust when they struggle up here? A lot of our guys have gone through that now.”