Pirates reliever Isaac Mattson builds momentum with another scoreless outing

Isaac Mattson wasn’t exactly sure what he’d do with his game ball June 7 after picking up his first MLB win and helping the Pittsburgh Pirates to a narrow victory over the Philadelphia Phillies.

Mattson, relieving starter Andrew Heaney with no outs, a runner on third base and a tie score in the seventh, performed his job to perfection, getting three outs to put out the fire and preserve the 1-1 score.

When the Pirates scored the go-ahead and winning run in the bottom of the seventh, Mattson came away with the victory.

While Mattson hadn’t figured out how he’d display the milestone memento, he had a firmer grasp on the implications of his performance.

“It’s just another step towards being able to be here consistently,” he said.

The 29-year-old righty, who’s from Erie and played college baseball at Pitt, joined the Pirates in November 2023 on a minor-league deal.

Beginning this season with Triple-A Indianapolis, the Pirates came calling initially in late May.

Mattson did well enough, posting a 3.00 ERA over three outings, but in less than a week, he was optioned back to Indianapolis.

However, on June 7, he was recalled again and that same day — a hectic one that saw Mattson arrive in Pittsburgh only hours before first pitch — he entered the game against Philadelphia, delivering a scoreless frame.

“If you’re going to get one, get one like that,” Heaney said of Mattson’s first career major-league victory. “That’s an amazing way to get it. He was here before, he came in and pitched well, pitched with emotion. And so I think he’s the right guy in that moment to come in and get three big outs for us right there. Just happy for him. He deserves it. He’s worked hard for it.”

Since then, Mattson has continued to perform in a manner suggestive of an extended stay in the big leagues.

On June 10, he pitched two scoreless innings, striking out three while walking none and allowing zero hits against the Miami Marlins.

Mattson also had an effective outing Thursday in Chicago, once again relieving Heaney.

Over 1 2/3 scoreless innings, he gave up no hits while walking and striking out one.

“He’s been pitching really well,” manager Don Kelly said. “He did a good job when he was up earlier this season and … we like him as a neutral guy against righties and lefties. (We) like his changeup against lefties.”

After Thursday, Mattson’s ERA is down to 1.17 on the year through six appearances and 7 2/3 innings.

He has struck out nine, walked two and opposing hitters are batting only .042 against him.

Mattson, originally a 2017 draft pick (19th round, No. 565 overall) by the Los Angeles Angels, was traded to the Baltimore Orioles in 2019 and made his MLB debut with the club in 2021.

But Mattson was released by the Orioles in spring 2022.

Unwilling to give up on his career, Mattson turned to the independent circuit, playing for the Frontier League’s Washington Wild Things and Atlantic League’s Southern Maryland Blue Crabs.

Parts of two solid campaigns got him a minor-league deal with the Twins in 2023, and while another crack at the big leagues wasn’t forthcoming in Minnesota, that winter he signed with the Pirates.

Mattson next tasted the majors at the end of 2024, appearing in three games out of the bullpen for the Pirates.

Kelly admitted he gets “chills” thinking of Mattson’s journey back to MLB, especially given his ties to Pittsburgh and having grinded it out in independent baseball.

Now, Mattson’s stock has steadily risen, as has Kelly’s trust in him as a leverage relief option.

“He’s just attacking guys, throwing everything for a strike, getting after the strike zone and he’s competing really well with all his pitches,” Kelly said. “He’s able to throw a lot of different things for strikes.”