"We're winning games," Counsell said, "and we are trying to find a way to win more games."
Counsell did not specify who would take Peralta's place Friday, though one option is right-hander Paolo Espino, who did not make his scheduled start for Triple-A Colorado Springs on Wednesday.
Brewers starters entered Wednesday ranked 24th of 30 Major League teams with a 4.54 ERA. They were last in the Majors with 12 quality starts, including two from Peralta, on April 11 and 16. In five starts since, he had a 8.61 ERA and a 1.051 OPS against.
It marks the second straight year that Peralta pitched himself out of the Brewers' starting rotation. He was the club's Opening Day starter in 2016, but was demoted to Triple-A in June after posting a 6.68 ERA in his first 13 starts.
This year, Peralta has a 6.08 ERA through eight starts. He has not made it through the fifth inning in either of his last two starts, including an outing against the Mets on Sunday in which he surrendered seven runs (six earned) in 4 1/3 innings. The Brewers rallied back from a 7-1 deficit to win, 11-9.
Peralta has not pitched relief since his Major League debut on April 22, 2012, against the Rockies. He went back down to the Minor Leagues after that appearance and was recalled in September to start, a role Peralta has filled ever since.
"There are important innings available in the bullpen and we think his skills can play very well down there, and help us down there," Counsell said. "It's a big change for him and it's not easy to make that transition during the season, but we will throw him in there, and we think he has a chance to be real good at it."
Asked what type of bullpen role Peralta might fill, Counsell replied, "out-getter."
While Peralta contemplated a fresh start in the bullpen, Garza continued to lead the Brewers' starting rotation. He did not surrender a Padres run until the sixth, when Wil Myers reached on an infield hit and scored on a Yangervis Solarte bloop to center field that just eluded Keon Broxton.
Those were two of the Padres four hits against Garza, whose ERA after five starts is 2.43. He opened the season on the disabled list with a groin strain.
"I want to keep progressing, keep improving, keep getting better," said Garza, who is throwing more offspeed pitches this season. "This is a new style for me. I'm just being able to have the confidence in my stuff and myself and the way the guys are playing defense. It is awesome."
"He's been a little bit unsung so far in this thing this year," Counsell said. "But he has pitched very, very well and has solidified that spot. He just keeps going out there and doing it."