Evaluating Boston’s catching situation
New Statcast metric highlights area of concern for Boston backstops
The Boston Red Sox have yet to announce which catchers will make the major league roster to begin the 2023 season. The picture may have become clearer after potential option Connor Wong strained his hamstring last week, leaving frontrunner Reese McGuire to compete with free-agent signee Jorge Alfaro and dark horse candidate Caleb Hamilton.
None of the backstops have much, if any, prior catching experience with the Red Sox organization. Thus, one thing is certain: Boston’s catchers will be closely monitored behind the plate to begin the season.
The precariousness of the situation may be exacerbated by the release of Statcast’s new catcher blocking metric, which accentuates the concerns of unreliability surrounding the team’s options.
Catcher blocking is a metric designed to “express the demonstrated skill of catchers at preventing wild pitches (WP) or passed balls (PB)” by assigning a probability “based upon several inputs, most notably: pitch location, pitch speed, pitch movement, catcher location, and batter/pitcher handedness” according to Savant.
Thanks to the analysts at Statcast, we have a new way of evaluating how effective catchers are at preventing runners from advancing via passed balls and wild pitches. Blocking is an often overlooked factor of the running game that can be just as important as exchange time and arm strength, categories factored into pop time.
Jorge Alfaro
Alfaro’s chances to make the roster have been on the rise this spring after signing a minor-league deal this offseason. The 29-year-old has seven hits in his first ten at-bats in Grapefruit League play, though runners are five-for-five off him in stolen base attempts.
Despite showcasing elite pop times over the past two seasons, Alfaro’s results have been mixed. He ranked seventh in MLB in pop time with the Miami Marlins in 2021 and recorded a career-high 43% caught-stealing mark over 21 attempts. In 2022 with the San Diego Padres, he ranked 3rd in the league in pop time but retired just 17% of base stealers in 30 attempts.
Disregarding the variability in results over the past two seasons, Alfaro’s combination of exchange and arm strength has been elite. But after analyzing his blocking it’s easy to see teams’ qualms regarding his ability behind the plate.
Over the past two seasons with Miami and San Diego, Alfaro accrued the worst catcher blocking runs score in MLB (-7) in addition to the second-worst rating in blocks above average (-26).
The good news is, when splitting up the data between 2021 and 2022, we can see that Alfaro was much improved with San Diego, albeit still well below average. There’s a reason he’s projected to play first base and DH for Colombia in the World Baseball Classic.
Alfaro is a toolsy player who has displayed impressive speed (28.7 ft/s - 85th percentile) and strength (115.2 max exit velo - 97 percentile) but needs to translate his athleticism to behind the dish to be an effective option for the Red Sox in 2023.
Connor Wong
Wong is in a similar position to Alfaro in that he recorded elite pop times (ninth best in MLB in 2023) and below-average blocking (-3 blocks above average). The major difference is he’s 26 years old with likely more room for growth at this early stage in his career.
Thus, he appeared to have the inside track for a spot on the Opening Day roster prior to his hamstring injury. The injury was documented as a Grade-1 strain, a mild categorization, meaning he could avoid a stint on the injured list.
Wong threw out 26% of base stealers in 92 attempts across the past two seasons with AAA Worchester, but his 17 passed balls align with his MLB struggles in the latter part of the 2022 season.
Like Alfaro, Wong accumulated most of his negative value behind the plate on misplayed easy chances, though he did outperform the former on tough chances in a small sample, converting all three of his opportunities.
Alfaro has more of a track record in the big leagues offensively (career 89 OPS+), but the perceived upside of Wong (.838 OPS & 35 XBH in 81 AAA G in ‘22) at and behind the plate may give him the edge.
Caleb Hamilton
Boston quietly claimed Hamilton off waivers from the Minnesota Twins on October 11th of last year…and promptly designated him for assignment about a month later on November 15th.
Still, the 28-year-old has had the opportunity to showcase his skills in major league camp this spring and is one of only four catchers on the roster with MLB experience. In 22 games with the Twins, he proved to be an adequate blocker behind the plate (0 blocks above average).
Hamilton’s solid offensive performance in AAA St. Paul in 2022 (.809 OPS & 21 XBH in 62 G) propelled him to the majors, but he struggled mightily there, striking out 14 times in 23 plate appearances. Hamilton has impressed this spring, however, racking up four hits (two XBH) and two walks in his first eight plate appearances.
It would take a continuation of this absurd offensive onslaught and solid defensive play for Hamilton to vault his way onto the 40-man and Opening Day rosters. It’s much more likely he will be an insurance option in AAA, though don’t be surprised to see him in a big league uniform sometime this season.
Reese McGuire
McGuire is the favorite to open the season behind the plate for Boston thanks in part to his torrid stretch to close out the 2022 season. McGuire slashed .337/.377/.500 in 108 plate appearances with the Red Sox after being acquired from the White Sox at the trade deadline.
It would be wishful thinking to assume the 28-year-old could replicate this performance considering he has been a decidedly below-average offensive performer over his career (87 OPS+) and his .337 average after his trade to Boston was aided by a .411 BABIP.
McGuire has a much weaker arm than both Alfaro and Wong, but his quick transfer still allows for a league-average delivery to second base.
Where McGuire separates himself from the other two is his blocking ability. He has shown the potential to be a strong controller of the run game in the past, ranking 16th out of 71 qualified catchers in blocks above average in 2021 with the Toronto Blue Jays (+6).
But McGuire posted more pedestrian blocking numbers in 2022 with Chicago (0 blocks above average) and struggled a bit comparatively with Boston (-3).
It’s likely that learning a new pitching staff mid-season impacted McGuire’s defense behind the plate. He did still showcase some of his elite blocking potential, converting eight tough chances.
McGuire also ranked 16th out of 60 qualified backstops in catcher framing runs (+3), another crucial factor in run prevention behind the plate - an impressive feat considering his aforementioned mid-season change of pitching staffs.
Conclusions
Due to his pedigree behind the plate in terms of framing and previous blocking success, McGuire appears to be the favorite as the Opening Day catcher. Alfaro and Wong both have the tools necessary to be impactful backstops thanks to their strong deliveries but need to prove they can be effective receivers. Hamilton should be a solid depth option in AAA.
It could be a little disconcerting that Boston does not have an elite blocking option behind the plate, especially considering four of the top eight blockers in MLB are within the AL East: Rutschman, Trevino, Kirk, and Jansen.
We don’t know how much the new rules will impact baserunning, but one thing remains for sure, catchers’ blocking ability will remain an integral part of the game in 2023. It would surely benefit the Red Sox if they can develop a wall of their own behind home plate.