Face it: We might never know how effective Mike Pelfrey would have been in the bullpen.

“Maybe we’ll find out — in five years,” Pelfrey joked after allowing only one run for the second consecutive start and leading the Twins — with a big bailout from Glen Perkins — to their fourth victory in a row, 2-1 over the Red Sox.

The Twins righthander, who is only in the rotation because Ervin Santana failed a steroids test, extended a streak of effective early-season pitching that the Twins haven’t often seen. In fact, Pelfrey will enter June with an ERA of 2.77, a remarkable turnaround for a pitcher whose Twins ERA was 5.56 in his first two seasons since signing a free-agent contract.

Almost as remarkable: The Twins moved one game out of first place in the AL Central with the victory, their eighth in the past 10 games, and Kansas City’s 5-1 loss in New York.

“We’ve got it going a little bit here,” manager Paul Molitor said.

So did Perkins, who stayed perfect by recording his 17th save in 17 opportunities, though he had to work a little extra for this one. He bailed reliever Blaine Boyer out of an eighth-inning jam by getting cleanup hitter Hanley Ramirez to fly out to right with the bases loaded.

That, and three more outs in the ninth, made Pelfrey a winner for the fourth time this season. He allowed only five hits over seven innings, and only once did Boston manage two hits in one inning — the second, when David Ortiz doubled off the left-field wall and Mike Napoli blooped a soft single to center. That was a bit of misfortune — Eduardo Escobar could have caught the double, but “he had a tough time with the wet turf, obviously,” Molitor said.

Pelfrey walked one and struck out four, throwing exactly 100 pitches over seven innings — a feat Molitor didn’t think was possible after he fought through that difficult second inning. In fact, as Pelfrey’s pitch count reached 80 in the fifth, Molitor already had relievers warming up.

“Mike was laboring for the second and third innings. It’s one of those games where you look at his pitches and how it’s going, and you wonder how far it’s going to go,” Molitor said. “Like a lot of guys have been doing in that rotation, they find another gear. We had people ready from the fifth on, and somehow Mike, to his credit, gave us seven innings.”

Maybe it was those relievers.

“I looked around and saw people out there in the bullpen,” he said. “I don’t think anybody likes to see the bullpen going, especially in the fifth.”

Pelfrey might have been the guy warming up, if not for Santana’s 80-game suspension. He was informed late in spring training that he was being moved to the bullpen — a decision that was rescinded when MLB announced Santana’s suspension.

“It just shows you, you never know how things will unfold,” Molitor said. “It’s nice that we’re getting depth from one to five in the rotation. … Mike found his way into the rotation, and he’s making the most of it.”

He made the most of only two runs Tuesday, because Red Sox righthander Clay Buchholz matched Pelfrey after giving up two first-inning runs. A pair of diving catches by right fielder Rusney Castillo helped limit the Twins to their lowest scoring total in Target Field since May 5.

Brian Dozier led off the first inning with a double to deep left, and he scored two outs later when Trevor Plouffe doubled him home. Kurt Suzuki followed with a double of his own, and the Target Field crowd that waited out an 81-minute rain delay surely expected the Twins’ recent scoring binge — they’re averaging 5.2 runs per game in May — to continue.

“It [took] really large two-out base hits there by Trevor and Suzuki to give us two runs early,” Molitor said. “But all the runs were scored in the first two innings.”

It didn’t matter to Pelfrey. Using a fastball that touched 94 miles per hour and a sinker that fooled the Red Sox, the righthander threw first-pitch strikes to 20 of the 25 hitters he faced.