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Astros 2018 Positional Defense in Review & 2019 Expectations--Catchers

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The final installment of my 2018 Astros defensive review will be at the catcher position, an area where the team experienced quite a bit of change during the offseason. Veterans Martin Maldonado and Brian McCann will be replaced by newcomer Robinson Chirinos and holdover Max Stassi. There are a few different elements that go into a catcher’s defensive value, so I will partition the analysis into separate phases.


The Astros ranked just above league-average in caught-stealing percentage (CS%) last season (29% CS, 25 of 85). Maldonado, who threw out 46.4% of would-be basestealers in 2018, allowed the fewest steals (18) in the game, by far, for players who caught at least 800 innings and also the fewest attempts (35). Conversely, Chirinos threw out a league-worst 10.2% (6 of 59) of would-be-basestealers in 2018. That was a career-worst rate for Chirinos, who had thrown out 31.2% (64 of 205) of basestealers from 2014-17 and still 25% over the course of his big-league career. Stassi allowed 32 steals in 43 attempts (26% CS) and McCann threw out nine baserunners on 28 attempts (32% CS).

There are certainly variables beyond a catcher’s control that factor into the caught-stealing equation—which Astros manager A.J. Hinch has cited as a team statistic rather than individual one—such as a pitcher’s time to the plate or baserunner’s speed, though there are some glaring differences in the Astros’ catchers’ attributes over the past two years. Namely, Maldonado’s arm (measured as average velocity, in MPH, on “max effort” throws, defined as the Top 10% of a player’s performance) graded out as one of the Top 3 in the game last year (87.5 MPH), according to Baseball Savant.

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Maldonado had an average poptime—number of seconds from the moment the pitch hits the catcher’s mitt to the moment it reaches the fielder’s projected receiving point at the center of the base—to second base in the Top 12 of baseball. Meanwhile, Max Stassi had the second-slowest average poptime to second base in baseball at 2.09 seconds. McCann wasn’t much quicker at 2.08 seconds and Chirinos was below average as well at 2.04 seconds (league-average on steal attempts of second base was 2.01 seconds).

According to Statcast, McCann’s arm (77.2 MPH) graded in the Bottom 3 of baseball last year while Stassi (79.3 MPH) and Chirinos (81.1 MPH) were the 11th- and 30th-worst, respectively. Interestingly, the Astros group of catchers all had roughly the same Exchange time—how quickly the catcher releases the ball, measured in seconds—last year (between 0.77-0.78 seconds). They were all in the lower 20% of average Exchange time for catchers. The differentiating factor amongst them was the strength of Maldonado’s arm.

Pitch Framing

In this area, I’d like to focus on the current Astros rather than reflect on the former ones (if you’re curious, Maldonado was good and McCann was near average). Stassi has displayed exceptional pitch framing skills. He ranked at the top of the league last year—tied with Tyler Flowers and Yasmani Grandal, two catchers highly-regarded for their defense—in RszC, the number of runs above or below average a catcher was worth based on pitch framing.

MLB: Houston Astros at Tampa Bay Rays Kim Klement-USA TODAY Sports

Chirinos, on the other hand, was one of the worst in the league last year with a -6 RszC, ranked 108 out of 117 catchers, and has -18 RszC since he entered the league in 2013. Houston Chronicle reporter Chandler Rome touched on the work Chirinos is doing with Stassi and Hinch during Spring Training. Rome described the acquisition of Chirinos well in his article, saying

“His presence offers an offensive remedy but creates a defensive enigma. The Astros place a premium on pitch framing, yet the signed one of the sport’s worst...Last season, Chirinos generated negative 0.011 called strikes above average, according to Baseball Prospectus. Max Stassi, for reference, led baseball with a 0.022 mark. Chirinos’ framing created negative 11.2 runs above average, the fourth worst among 117 major league catchers whose work was evaluated.”

MLB: Los Angeles Angels at Texas Rangers Jerome Miron-USA TODAY Sports

The Astros have a strong history of valuing pitch framing and have already begun advising Chirinos on adjustments he will need to make, as noted by Rome. Chirinos is in no better place to improve his pitch framing, and if he can do so it will provide a huge boost to his and the club’s value at catcher.

Defensive Fielding

According to Baseball Reference, the Astros saved 12 defensive runs above average (Rdrs) as a unit at catcher in 2018, which ranked fourth. Stassi was a major contributor to the Astros defensive value at catcher, where he provided +9 Rdrs. Chirinos was -11 Rdrs for the Texas Rangers last year, though he’s hovered roughly around zero Rdrs over the course of his career (he was +3 Rdrs prior to 2018). Maldonado was worth +1 Rdrs while in Houston, +3 Rdrs overall in 2018, and McCann was +3 Rdrs last year. Chirinos’ ability to provide even just average defense for the Astros would be a big benefit.

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Maldonado ranked in the Top 5 of qualified catchers (min. 800 innings) in “Remote,” “Unlikely,” and “About Even” plays made (small sample disclaimer). Chirinos, a converted infielder, was on the lower end of the spectrum of the Inside Edge Fielding categories, though Stassi did well. It wasn’t all roses for Maldonado defensively, however. He had the most past-balls (13) amongst catchers with a minimum of 700 innings—which reared its ugly head in the postseason—and allowed the second-most wild pitches (53).

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As a team, the Astros had more past-balls (15) and wild pitches (67) than league average, though maybe that’s to be expected given the club’s emphasis on spin rate and breaking balls. Regardless, I don’t expect either past-balls or wild pitches to be an area of concern in 2019, considering Stassi and Chirinos are not poor in either regard.


The Astros will have to deal with the departure of one of the better defensive catchers in the game and another who had a strong veteran presence in the clubhouse. Maldonado’s ability to limit opposing teams’ speed on the bases and McCann’s influence on team chemistry will be difficult to replicate. Stassi and Chirinos will each provide more at the plate than the departed players, but the Astros should be expected to be quite a bit weaker in stopping the run-game in 2019.

Stassi does have elite pitch framing skills, though, and we’ve learned Chirinos has already begun refining his skills in that regard, where former big-league catcher and current Astros skipper A.J. Hinch should be a valuable resource. Chirinos’ ability to serve as a threat to basestealers and become an adequate pitch framer and defensive catcher will be areas of emphasis. Additionally, Stassi got off to a hot start at the plate in 2018 before cooling significantly as the season progressed. I am hopeful a full season in the big-leagues has provided Stassi further experience that will translate into greater consistency and longevity at the plate. Ultimately, the integration of Chirinos and Stassi into elevated roles at catcher will be an important development for the Astros in 2019, as they revamp 60% of their starting rotation.