Astros pitching turnaround may have unsung hero no one expected

The Houston Astros spent most of the offseason looking for an upgrade at backup catcher for Yanier Diaz. The club made it clear that it didn't trust Cesar Salazar in that role, so much so that even now, the club DFA'd him in favor of Collin Price, even with Diaz laid up on the IL. A big reason for that confidence is that the Astros found Christian Vazquez.

A big reason for the urgency to replace Salazar had to do with Diaz's limitations. Though he came off a down year in 2025 and hadn't hit much before going down this season, Diaz's bat is what keeps him in the lineup. Vazquez, on the other hand, has never been much with the bat, and even less so now in his age-35 club. However, Vazquez's calling card has been his glove, and that's still the case today.

To that end, Astros insider Chandler Rome pointed out a stark difference that, indirectly, relates to who is behind the plate. It's well known that Houston's pitching staff was atrocious to begin the year, and is now starting to improve, and Rome speculates that who is behind the plate might be the reason why.

With Vazquez as the primary starter, the Astros pitching staff has a 3.99 ERA. With Diaz starting behind the plate, that number is 5.75. The samples are pretty similar as well, with Vazquez serving as the lead catcher for the 33 games, and Diaz running the show primarily for 35 contests until he got hurt.

Christian Vazquez has been a boost to the Astros pitching staff, but it's impossible to tell to what degree

Catcher is such an important defensive position, but measuring the performance of an individual catcher can be nearly impossible past a certain point. We can look at stats like caught stealing rate and passed balls, but that only tells part of the story. We can look at more advanced metrics such as pop time, arm strength, and framing runs, but again, those are just a few pieces of the puzzle.

For example, a strong-armed catcher with a great pop time can still be subpar at cutting down would-be base stealers if he struggles with accuracy. And of course, those are all drastically different skill sets from what pitch framing or blocking require.

Furthermore, the most important part of catching -- calling games and managing the pitchers (strategically and emotionally) -- is basically impossible to quantify. Therefore, it makes it hard to separate an improvement in pitching performance from the catcher, and a drastic pivot, as we've seen with how Houston's hurlers have performed, might have nothing to do with the catcher at all and everything to do with the pitchers themselves getting better. To that end, it's worth considering what else changed around the beginning of May when Diaz went on the IL.

For one thing, Spencer Arrighetti didn't get called up until April 15, and while he had a good four-start run with Diaz, most of his success came when he won AL Pitcher of the Month in May, when he was throwing to Vazquez.

In addition to Arrighetti, productive starters like Peter Lambert and Kai-Wei Teng either weren't in the rotation before Diaz got hurt or have pitched to Vazquez for the majority of their starts, making Vazquez look better even if that can't be fully proven or disproven.

On the flip side, Diaz caught the likes of Lance McCullers Jr., Cristian Javier, and Ryan Weiss, for example. It doesn't matter if you're the second coming of Johnny Bench; you're not going to coax good results out of that group.

There's no doubt that Vazquez is the superior defensive player, but the impact he has had on the pitching staff is impossible to ascertain. He's certainly earned a bit more run once Diaz returns, but overall, the pitching will need to continue on this positive trend, no matter who is behind the plate, in order for the Astros to truly contend.

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