DENVER — It takes a lot to surprise Isaac Mattson in the game of baseball.
The Erie native and Pitt product has played in the Frontier League and Atlantic League. He’s been traded, released and removed from the 40-man roster. The right-handed reliever also became a reliable setup man in 2025, pitching to a 2.45 ERA in 44 games, and began this season as one of the Pirates’ primary bullpen options.
But after back-to-back scoreless outings against the Phillies in mid-May, Mattson was caught off-guard when he learned he was being optioned to Triple-A Indianapolis.
“I didn’t expect it,” Mattson said. “But leaving that meeting, there were things that I kind of recognized before getting sent down that were adjustments I needed to make.”
In the latest indication of Mattson’s strong character and ability to persevere, he took the demotion in stride, improved as a pitcher and returned a wiser person and better leader because of it, all while setting an incredible example for some of the Pirates’ younger players.
What the Pirates did with Mattson was similar to how they handled David Bednar last season, when they used a lower-pressure environment to help their former closer adjust and rediscover a certain level of performance.
Before Mattson left, the Pirates emphasized the need for him to become less reliant on his four-seam fastball, which he was throwing a career-high 80.7% of the time, leading to a 4.12 ERA through 21 appearances.
In two games since Mattson was recalled on June 13, we’ve seen a much different pitch mix, with Mattson more wiling to use his slider, changeup and curveball.
“He did exactly what we’ve asked him to do,” Pirates manager Don Kelly said. “We’ve asked him to be a little bit more aggressive with his mix. ... Did that. Got results. We know the character of teammate he is.”
How Mattson handled himself through the entire ordeal should tell you a lot about his off-field makeup, how he’s wired and why he’s universally respected within the Pirates clubhouse.
There was no pouting. Mattson said “it was pretty instant” when it came to orienting his thinking toward getting better and going to the Minor Leagues to do it, and he recognized the canvas Triple-A would provide.
Results still matter, obviously. But there’s a larger safety net to try new things and fail. The toughest challenge became logistics.
Isaac and his wife, Devin, have a young son (Teddy), who was born last February. They decided it made the most sense for Devin and Teddy to remain in Pittsburgh, so Isaac went to Indianapolis alone. He actually lived with Thomas Harrington and Hunter Barco, occupying space upstairs in the house they rent and insisting on paying them via Venmo for the stay.
“I know what it’s like be down there,” Mattson said. “Regardless of what their situations are, if you stay somewhere, you need to make it right."
There was also a funny situation on the road, which speaks to Mattson’s unique upbringing. He’s one of eight and has always lived a modest life. Mattson tapes a cardboard box to his locker to store socks and others things because he’s always done it and likes it; no need to order something fancy.
He likes his iPhone 3; no need to change. And when Indianapolis traveled, he and Billy Cook decided to save money by rooming together, a decision that seemed to confuse some of their younger teammates.
“We were talking to the guys, and everyone was like, ‘Dude, I’d never want to share a hotel room,’ ” Mattson said. “Being in that position, there’s a lot of expectation to spend the money and not think twice.
“Just trying to be as frugal as we can in those situations because you never know when you’re going to get your next shot in the big leagues.”
In the Minor Leagues, if you stay by yourself, you pay 50% of the room cost. If you share a room, it’s free.
Meanwhile, teammates saw how much Mattson cared about his family, about getting himself right and doing everything possible to return to the big leagues.
“He sets a good example for all the guys down there and even guys up here on hard work and making sure that’s really focused,” Cook said. “I’m sure he’s learned from being around successful guys up here. He’s willing to share that with the younger guys down there, too."
Mattson credited Indianapolis pitching coach Drew Benes for helping him follow through on the changes the Pirates wanted him to make. He also texted with Bednar, learning more about how Bednar handled his situation and trying to follow that example as much as possible.
In nine games with the Indians, Mattson had a 1.86 ERA across 9 2/3 innings, walking six and striking out 11. Mattson has pitched twice since returning, allowing a solo homer Wednesday and nothing more across 2 1/3 innings, striking out three.
It matters for Pirates fans because Mattson’s possible return to his 2025 self could go a long way toward addressing this team’s biggest weakness: the bullpen. Like Bednar, Mattson has become a key veteran.
Leadership has always come natural to Mattson because of what he’s experienced and his warm personality, and he could play a crucial role if the pitch-mix changes work.
So far, it’s been solid. Mattson’s slider has a 33.3% whiff rate, while his changeup has been more effective, as well. That homer came on a down-and-in slider to a righty (Zack Gelof) who hit it just 363 feet.
But as Mattson knows all too well, there are countless twists and turns in this game. All you can do is work hard, listen, treat people right and carry yourself as a professional, and often things will work out.
“Definitely with my experiences, it all adds perspective," Mattson said. "I know I’m not the perfect version of myself yet. But I’m continuing to learn about myself as a baseball player and human being. Just trying to be better each day.”
Jason Mackey: Jason.Mackey@pirates.com and @JMackey_PGH on X.