Matt Chapman Is a Weapon of Mass Destruction

Matt Chapman has long been a sabermetric darling, but it was largely on the basis of combining elite defense at the hot corner with merely above-average offense. While he’s always hit the ball hard, his rather low BABIPs and middling contact skills have been a ceiling on his production at the plate. With his glove in decline and entering his age-30 season, it was an open question as to how lucrative he would find free agency at the end of the season. But Chapman’s 2023 season has been an offensive tour de force, with a seasonal line of .364/.449/.636, a 202 wRC+ and 2.0 WAR as of Thursday morning. The Blue Jays have gotten better than a .700 OPS at only three positions this season (first base, third base, shortstop), and Chapman’s sterling performance is one of the main reasons the offense has still been able to rank sixth in the American League in runs scored.

Just to get it out of the way: Chapman’s not going to hit .364 for the 2023 season. Looking at the zBABIP that ZiPS calculates for him, it thinks his BABIP should be more like .300 based on how he’s hit, not the current .461 figure. But what does look like it’s here to stay is the level of power he’s displayed; if he were a computer program, David Lightman would have skipped Global Thermonuclear War and played Matt Chapman instead. An average exit velocity of 95.6 mph and a hard-hit rate of 66.7% are in ultra-elite territory, and small sample sizes for data like these are relatively meaningful. Chapman’s barrel percentage so far has approached a ludicrous 30%, a number nobody’s been able to touch in a full season (Aaron Judge at 26.2% in 2022 is the only player so far to beat 25%).

You can argue that Chapman is actually slightly underperforming based on his power numbers. A .636 slugging percentage is quite exciting — a number large enough to lead the league fairly often. But Statcast’s xSLG thinks his slugging percentage should be even higher, at .716. ZiPS agrees with this generally, giving him a zSLG of .703 and a zHR of 6.8 compared to his actual five round-trippers. Putting up an xSLG of .700 is something elite power hitters do; only 46 players in StatCast history have managed that at least once. Here’s the full .700 Club and how they fared for the season overall; I’ve listed each player’s best month rather than list all of the individual months:

Not all of these players were actually elite hitters over the long haul — I’m looking at you, Danny Valencia — but this group as a whole did finish the year with top-notch offensive seasons. Of the 33 seasons listed here in which the player in question finished with at least 500 plate appearances, 27 featured at least 30 homers, 31 a slugging percentage above .500, and 22 a wRC+ above 139 (Chapman’s career-best number so far). Overall, in all the seasons in which a player had a month with a .700 xSLG, the average final result was 34 homers, a .569 slugging percentage, and a 148 wRC+.

So what has changed for Chapman? Sports Illustrated talked about Chapman spending the offseason revamping his swing.

By the end of 2022, Chapman decided he would revamp the “load” portion of his swing, ditching the subtle leg kick he found inefficient and inconsistent, at times. Over the offseason, Chapman replaced the kick with an even subtler toe tap, gently pushing off the ground before sliding forward into attack position. The results have been immediate, as Toronto’s hot corner has toe tapped his way to the hottest start in baseball.
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Last year, Chapman found himself “stretched out” at the plate. He would step forward out of his leg kick too far, throwing his swing off balance and pushing his bat path under the ball. He became the king of the warning track fly-out, posting the lowest HR/FB% of his career. The 2023 toe tap shortens him up, skimming his front foot along the dirt into the desired plant location. Every tap isn’t identical, but Chapman’s got more room for error now than with the kick.

The answer to whether or not this change is the reason Chapman has hit so well is something that’s ultimately unknowable. But there’s data that’s consistent with this explanation. For one, he’s not being any more selective at the plate, nor has he tinkered with the plane of his swing, but he’s making significantly increased contact. Increasing contact rate and also increasing the quality of the contact and not changing the mix of pitches you’re offering at is a difficult needle to thread. I recommend checking out the whole SI article linked for more of this.

Since this is me and I have access to a fancy-pants projection system, I want to look at the consequences of Chapman’s improvement. Suffice it to say, ZiPS and the other projection systems like him a lot more in May-to-September than they did coming into his season. ZiPS has gone from a preseason wRC+ of 127 to a RoS of 138 over the course of a month, a gain of 11 points. There are similar jumps in Steamer (112 to 123) and THE BAT (113 to 128). With two WAR already banked, ZiPS now has Chapman finishing with 6.7 WAR on a line of .275/.368/.516 with a wRC+ of 152. That WAR now ranks third in baseball, behind only Judge and the revitalized Acuña. And this is using the simpler in-season ZiPS model, rather than the full one that has access to all the StatCast data. With that data included, ZiPS projects Chapman to finish at .293/.383/.587 for 2023, which puts him even more squarely in the MVP mix, especially if Judge’s sore hip proves to be a hindrance.

And since Chapman is a free agent at the end of the season, there are also financial repercussions. He’s moved the needle enough that he’s looking at a larger contract than appeared likely a month ago. Coming into 2023, ZiPS projected him to get a five-year, $113 million contract when he hit the open market:

As of Thursday morning, ZiPS now projects him to make $149 million over those same five years. I cannot remember ever running a projection and having a dollar figure move that much ($36 million) over the course of a single month. I even went back and checked 2022 Aaron Judge month-by-month and never got that much of a change in trajectory. And this is despite the continued erosion in his defensive expectations.

However Chapman’s doing it, his 2023 is tallying wins for the Jays and future dollars for him. The Blue Jays have had a bunch of things go wrong this year, but Chapman going right is a big part of keeping them firmly in the playoff picture.