On Wednesday, he harnessed his stuff and looked like the pitcher who established himself as the Brewers' top prospect.
Peralta gave up four hits and three walks while striking out four over 5 2/3 innings in Triple-A Nashville's 4-0 blanking of Round Rock. It was the first time this season the big right-hander registered at least five scoreless frames.
"I feel good [about this start]," Peralta said. "I've been bad at times this year; today, I finally got one."
The start brought him a little bit closer to the track he seemed to be on through the first month of the season. In four of his last five outings, the native of the Dominican Republic has limited opponents to three earned runs or fewer. That's something he didn't do once from May 17-June 1, a stretch that saw his ERA climb to 6.83.
The only hiccup in his recent run came in his previous outing on June 22, when he retired only two batters and was charged with four runs against Oklahoma City.
"You know, when you're struggling, you've got a lot of things going wrong," Peralta said. "But I know I can do it. I've struggled before, I know I'll get out of it. I stay positive and work hard and do my best."
Against the Express, he was as close to his best as he's been in a couple of months. Peralta (3-8) got Brad Nelson to hit into an inning-ending double play in the first, leaving runners at the corners. The 23-year-old also stranded a runner at third in the third, then faced the minimum until walking Ryan Spilborghs on his 71st and final pitch.
"I've been struggling this year a little [with command], but it was working tonight," Peralta said. "Locating pitches better, getting ahead in counts, that's the thing I've been working on. Command my pitches, command my fastball. That's it."
The early exit was due to cramping in his legs, something Peralta downplayed.
In his last five outings, MLB.com's No. 40 overall prospect has a 3.80 ERA over 23 1/3 innings, striking out 23 and walking 16. For the season, he's struck out 67 and walked 48 in 77 1/3 innings.
Location remains Peralta's biggest issue. He can blow pitches by just about anyone but knows his impressive velocity won't do much good if he's not in the strike zone.
"I've been working hard in my bullpen sessions, so today on the mound I felt great," he said. "I just want to keep going out there and doing the same -- don't try and throw too hard. Make the pitches and locate it."
This season has been Peralta's most challenging since he pitched in the Rookie-level Arizona League in 2006, the year after the Brewers signed him as a non-drafted free agent. Last year, he struck out 117 over 119 2/3 innings and compiled a 3.46 ERA at Double-A Huntsville before a promotion to the Pacific Coast League. In five Triple-A starts, he was 2-0 with a 2.03 ERA.
After four solid outings to begin this season, Peralta got his first Major League callup and made his Milwaukee debut against the Rockies on April 22.
Catcher Dayton Buller provided most of the offense for the Sounds, homering twice. Sean Halton also went yard.