PITTSBURGH -- Mitch Keller looked like his 2023 self again on Monday night at PNC Park, bouncing back from a shaky start to the season by rattling off six innings of two-run ball to lead the Pirates to a 7-4 victory over the Tigers.

To do it, he put one pitch on the back burner and leaned heavily on his fastballs again.

Over his first two starts of the season, in which he allowed 10 runs over 11 frames, Keller used his cutter more than any other pitch, throwing it 27.8% of the time. It wasn’t particularly effective, though, especially in his last start against the Nationals on April 3, when they rattled off two run-scoring hits against it in the second inning.

That shaky start, plus a slight drop in fastball velocity this spring that carried into the regular season, may have concerned some fans out of the gate, but the team has plenty of faith in the pitcher they inked to a five-year, $77 million contract extension in February.

“Mitch Keller is way down the list of things that I’m worried about,” general manager Ben Cherington said with a chuckle on his 93.7 The Fan radio show Sunday.

Keller showed why his team has that faith in him on Monday. While he was far from perfect out of the gate, walking two of the first three batters he faced and surrendering a run in the first, he knew had his mojo.

"Even in the first inning where I had two walks, which is kinda uncharacteristic, I felt really good about how it was coming out,” said Keller. “It was just about dialing it back into the zone. Once I went out there for the second, I kinda knew that I was pretty locked in with my stuff."

Keller’s success was fueled by his fastballs, especially the sinker. His velocity ticked up back to its 2023 norms, averaging 95 mph on the four-seamer and 93.8 mph on the sinker, and he was able to move it around. While the sinker is not normally his strikeout pitch, he was able to get six of his nine punchouts with it.

“It's really good going forward just to know how we set it up, that it's still there,” Keller said. “That we can get strikeouts with it, that it doesn't have to be offspeed.”

It’s obviously good news that the fastball played like it did in his All-Star campaign last year in terms of velocity and execution, but manager Derek Shelton had a clear preference for which one was more encouraging for him.

“The velo is going to trend up and down at times depending on where he's at,” Shelton said. “The ability to execute the fastball command was the most important thing."

Keller threw 58 fastballs -- 39 sinkers -- in his 98-pitch outing, and leaned on his breaking stuff differently than he had earlier this season. He got a couple strikeouts with the curveball early and threw it 17 times, while he threw the cutter just 12 times (12.2%). There was just one instance last season when he threw a lower percentage of cutters in an outing (July 28, 11.1%).

"It was in the game plan, but I think just with how the game was going, and what [Tigers hitters] were telling us, and just the swings and the reactions we were getting with the sinker, was the driver of that,” Keller said. “There was no mid-week thing like, 'Hey, we're not going to throw that many cutters this week.' It was just kinda how the game was going, and what they were telling us, how they reacted."

That’s the chess match of baseball, and what Keller is able to do when he is locked in. It’s what the whole rotation has done of late. Keller’s outing was the Pirates’ fifth straight quality start, helping fuel this 9-2 start, the team’s best since 1992.

“That’s where it starts,” said Bryan Reynolds. “That’s huge. Plus, the bullpen has been lights out. That’s a good recipe right there.”

Keller seemingly always has a chance at a quality start because he’s now gone at least five innings in 34 straight starts. That’s imperative for a team that needs him to head the rotation.

"That's the maturation we've seen of Mitch Keller, of him being able to execute pitches, him being able to get himself out of jams,” Shelton said. “I think it's also one of the reasons we made a commitment to him, because that is so important."