After a pair of come-from-behind wins, the Twins try to finish off the visiting Astros on Sunday.
Minnesota starter Kyle Gibson allowed four runs and nine hits in three innings, but four relievers combined to yield one hit and strike out 10 in Saturday's 6-4 victory.
While Twins starters are last in the majors with a 5.19 ERA, their bullpen is second at 2.93. Their relievers have allowed one run and fanned 18 over 17 innings of the last three games.
Minnesota (47-60) might again need to rely on its relief corps if scheduled starter Mike Pelfrey (4-9, 5.31 ERA) is unable to bounce back from a rough performance.
The right-hander had a 2.28 ERA in his first four July starts, but closed the month by allowing four runs in four innings of a 7-2 loss to Kansas City on Tuesday.
"It looked like he was picking at the plate an awful lot rather than attacking the zone,'' manager Ron Gardenhire said about Pelfrey, who yielded eight hits and threw 93 pitches. "One thing he's been doing is attacking the zone. Pace of the game means a lot. He kind of put everybody on their heels and he understands that."
Though he has not faced the Astros (36-73) since 2010 while with the New York Mets, Pelfrey has allowed three runs over 22 1-3 innings to win three straight starts against them.
While Minnesota's bullpen has shined, Houston relievers rank last in the majors with a 5.13 ERA. They've allowed six runs, nine hits and walked seven over 7 2-3 innings in the series.
Houston's bullpen has posted a 6.55 ERA and blown eight saves while the team has dropped 24 of 30.
"This is arguably the toughest stretch which I've witnessed, whether it's as a player, coach, manager, of bullpen woes,'' first-year manager Bo Porter said.
The Astros will recall Brad Peacock (1-3, 8.07) to start Sunday in place of Dallas Keuchel, who pitched 1 2-3 innings of relief in Friday's 4-3, 13-inning loss.
Peacock, who last pitched in the majors June 8, is 6-2 with a 2.73 ERA in 14 games and 13 starts for Triple-A Oklahoma City.
"He's thrown the ball extremely well," Porter told the Astros' official website. "That's obviously factored into the decision-making."
The right-hander opened the season in Houston's rotation, but went 1-3 with an 8.44 ERA in five starts before he was moved to the bullpen and sent down to the minors twice.
Peacock has never faced Minnesota.
Twins leadoff hitter Brian Dozier is batting .304 during a 10-game hitting streak.
Houston rookie outfielder Robbie Grossman is 10 for 20 in his last six games.