MILWAUKEE -- Developing Mitch Keller into a reliable starter is key for the Pirates' future. Once Pittsburgh’s top prospect in 2019, Keller has shown glimpses of becoming the pitcher the club has hoped he’d be this season.

That continued on Tuesday in the Pirates’ 4-2 win against the Brewers at American Family Field, as the right-hander threw his sixth quality start over his past nine outings.

“It was really a good team win,” reliever Chase De Jong said after notching his first career save. “That’s the best I’ve seen Mitch throw the ball. That was phenomenal.”

As Keller’s matchups with his first two batters indicated, his performance ended with a lot of strikeouts. The right-hander started the game by fanning Brewers designated hitter Christian Yelich and shortstop Willy Adames. Then, he struck out eight more over his outing for a career-high 10 punchouts.

“He's a young pitcher with a really good arm, and I think we saw that,” Brewers manager Craig Counsell said. “He was very locked in with his breaking ball tonight and then the fastball -- that's as big of velocity as we've seen from a starter. He got on a roll, and we weren't able to upset that at all, that rhythm that he got into.”

Aside from a fourth inning that saw Keller give up a two-run homer to Kolten Wong, he was in full control on Tuesday. He finished his outing allowing just four hits, two runs and two walks with 10 strikeouts across six strong innings.

“After he gave up the homer, there was no panic in him,” manager Derek Shelton said. “He continued to execute pitches and his stuff continued to get better, and I think that’s just a sign of him maturing as a pitcher.”

Keller also set a new career-high with 33 called strikes plus whiffs, which passed his previous high of 32 on Aug. 23, 2019.

“Attacking the zone and just having high velocity tonight,” Keller said on the key to his outing. “Everything was pretty much on tonight, so I think that’s a good contributor to having career-high stuff.”

Keller’s outing on Tuesday was much needed to get the right-hander back on track. In his past two starts, he had gone just a combined 5 2/3 innings while allowing 12 runs (six earned) on 12 hits, and he left his Aug. 16 start against the Red Sox with right shoulder fatigue.

But the right-hander seems to be in a better place on the mound now.

“It’s huge,” Keller said. “It just gets you back on track and just gives you even more confidence. This week, leading up to the start, [I] focused on recovery [from the fatigue], making sure I was getting good sleep and staying hydrated. Just all the little things. All the little things add up to feeling really good.”

This start was not only a major confidence boost for Keller, but it also showed his potential. Since July 11, he has had six outings in which he went six or more innings, five of which he has allowed two runs or fewer.

And as the season approaches the end, it’s an encouraging sign for the Pirates that Keller continues to improve on the mound. 

“[I] just have to keep going,” Keller said. “I’m not trying to look too much into everything, but I’m feeling the way I used to feel when I was dominant in the Minor Leagues, just that same kind of feeling out there. Just calm, cool and collected.”

Keller has surely had his fair share of ups and downs this season. He had a 6.61 ERA through his first seven starts in 2022 and was moved to the bullpen for two games in the middle of May because of his struggles.

But since moving back to the rotation on May 31 to face the Dodgers, the 26-year-old has a 3.69 ERA with 75 strikeouts across 85 1/3 innings in 16 starts.

“Starting pitcher is definitely where I want to be,” Keller said. “And I think I’m capable of being a really good one at this level. It feels great to be back and just feels good to have good outings, too.”