Steven Matz Has Quietly Been A Great Acquisition

Once the trade deadline passed, the fallout in Boston seemed to be centered around the acquisition of Dustin May, and a lack of further buy-in from the Red Sox front office. There was, however, little to no discourse surrounding the acquisition of veteran reliever Steven Matz. 

Matz, 34, is in the final year of a four-year contract he signed with the St. Louis Cardinals entering 2022. He was a starter for most of his career, and he gradually transitioned to the bullpen across the past four years to the point where this season he has been used almost exclusively in relief. A 34-year-old left-handed reliever without a true fastball? It makes sense why there was no outcry of excitement in Boston when news broke that Matz would be the newest member of the Red Sox. 

And yet, so far, Matz has excelled in Boston, allowing just one run off two hits and a walk in his first six appearances since the trade. What is odd about Matz is the fashion in which he induces outs. He is uber-reliant on his sinker, which he has thrown around 60% of the time this season and has generated a Statcast run value of 10, which is fifth among all sinkers in MLB. Even in his days as a starter, Matz would always throw the sinker more than half of the time. Although the peripherals behind the sinker have not evolved in his career, Matz is giving up less hits and hard contact than ever with it this year. He pairs that sinker with a slow curve, as well as a seldom-used changeup. 

What he has done so effectively this season is pound the strike zone with movement. Matz has a walk rate of just 4.3% this season -- the lowest of his career. He does not strike a ton of guys out, and he does not give up a ton of hard contact. In effect, Matz is an old-school, pitch-to-contact specialist, in a league where that archetype has faded. 

(Tj Stats)

As seen above, Matz has average stuff, however the results have been great. With effective tunneling of his sinker and curveball, Matz can induce mediocre contact consistently. That is, if he can generate swings, and throw strikes, both which he has excelled at in 2025.

Another effective way to limit quality contact is by limiting a hitter’s ability to pull the ball in the air. Matz ranks in the top 35 among all pitchers in limiting that result. What he lacks in stuff he makes up for with his elite command and location. Matz has a Location+ of 111, which ranks 14th among all pitchers with 50 or more innings, and first on the Red Sox.

What we have seen the Red Sox do with Matz so far is simplify his arsenal. He is throwing the sinker more in August than any other point this season, while cutting his slider out of the mix and dropping his changeup usage. Expect to see Matz continue to pound the zone with sinkers while mixing in a curve every now and again, mainly to keep hitters off balance.

In an era where so much pitching value is placed on the ability to induce swing-and-miss, it is refreshing to see a veteran spin the baseball, throw strikes, and generate outs. Matz is by no means an elite pitcher, but he has proved to be a valuable addition to Boston's bullpen, and will play a key role as the season winds to a close.