What’s Up With Max Muncy?

Muncy's elite plate discipline may be working against him this season.

Max Muncy has become one of my personal favorite hitters ever since his breakout two years ago in 2018, and for good reason. He does pretty much everything I like: hits for power, loves to walk, and is versatile, as he is able to play everywhere in the infield except for shortstop. He was one of the league’s best hitters from 2018 through 2019, with a 146 wRC+ in that span, which ranks eighth among qualified hitters in that span, showing that he is quite capable with the bat.

This season, though, has been particularly difficult to watch as a big Muncy fan. His great numbers from the prior two seasons have regressed big time, as he is running a .189/.330/.373 triple slash with less than a week to go in the season. It is a far cry from the Muncy we’ve come to know and love over the last two years. There’s not much that Muncy can do at this point to salvage the regular season, but fortunately, the Dodgers haven’t missed a beat, as they have the best record in baseball and are holding true to their preseason expectations as World Series favorites. The struggles for Muncy though, are concerning, and are worthy of a closer look.

The good news for Muncy this season is that he is still walking a lot, keeping up that reputation as being one of the hitters with good plate discipline. Muncy’s 15.9% walk rate this season is right in line with where it was last season and is right up there with the best in the league. It is good to see Muncy still with an elite walk rate, as it is unlikely that his shortcomings this season are due to issues with his approach and him starting to chase bad pitches, which would be a huge red flag. The analysis part would be much quicker, but still, I prefer that to not be the case. For Muncy this season, his chase rate is even lower than it was last season and his strikeout rate is nearly identical to last season as well. These are good signs on the surface, and the cause for Muncy’s struggles this season are likely hidden a bit deeper beyond the surface.

A major item that stands out immediately when looking at Muncy’s profile is his low BABIP. It is true that Muncy is dealing with some BABIP-related issues this season. He’s currently sitting at just a .207 BABIP mark, which is one of the five-lowest in baseball this season and his overall low batting average of .189 is also among the lowest and doesn’t look all that undeserved, with a better, but still not great, expected batting average of just .239 per Statcast, in just the 29th percentile. Muncy may not be getting the most batted-ball luck this season just by taking a quick look at some of his expected statistics, but for the most part, Muncy’s struggles this season cannot be blamed on just bad batted-ball luck and BABIP.

One of the first things I like to look at when a should-be good hitter is not performing well and struggling is to see if he is being pitched to differently. In the case of Muncy, it looks like this is a factor. Specifically, Muncy is seeing fewer fastballs this season:

Indeed, Muncy has gone from having about 55% of pitches seen being fastballs to now just around 48%. Keep in mind that the league average fastball rate is around 56%, so Muncy was right in line with the league average last season, but is no longer. Also, Muncy’s drop in fastball rate is one of the 20 largest in baseball from 2019 to 2020, making it look like a pretty significant drop.

It is also significant because Muncy has been one of the best fastball hitters in the last two seasons. In terms of slugging percentage, he’s actually been the best, and he’s second in terms of wOBA:

Top SLG & wOBA on Fastballs 2018-2019 (min. 1000 PA)

From this, it certainly seems as if it’s a good idea to stop throwing Muncy so many fastballs. He is still hitting fastballs well this season, with a .580 SLG and .384 wOBA combo, with even better expected versions of those stats, but Muncy seeing fewer fastballs overall appears to definitely be playing a role in his overall struggles this season, and that is especially because he is not making it up on the other pitch types. In a change from last season, Muncy is struggling mightily against non-fastballs this year. Looking at all hitters with at least 150 plate appearances this season, Muncy has been one of the worst hitters in terms of both SLG and wOBA on non-fastballs:

Max Muncy: 2020 Non-Fastball SLG and wOBA

So, Muncy is seeing fewer of the pitch types that he does the most damage on and is not making up for it by getting good results on the other pitch types. It looks like we have a good preliminary understanding as to why Muncy is struggling this season, but this is probably not the full reason.

It’s possible that Muncy’s elite plate discipline may be working against him here. Since he is struggling greatly on non-fastballs, it would perhaps make sense for Muncy to be more aggressive and jump on fastballs when he does get them. Looking at Muncy’s swing rate on fastballs, it has actually decreased year-over-year to a minuscule 36.9% rate, among the lowest in the game:

2020 Lowest Fastball Swing %

Now, this alone is not a bad thing. Muncy is already an infrequent swinger, with a 37.2% overall swing rate, one of the ten lowest in the game. Muncy has typically been the type of hitter who is exceptionally good at laying off bad pitches and capitalizing on mistakes. Although, it does look curious then, that Muncy’s fastball swing rate is so low when looking at where in the strike zone Muncy is getting his fastballs:

That looks like an awfully large amount of fastballs sitting dead-center and just begging to be ripped. Indeed, they are, and we can quantify it. Using the Statcast attack zones as detailed here, we can look at how many fastballs Muncy is getting in the heart of the plate, essentially pitches in the centermost portion of the plate where hitters are expected to do most of their damage. Here is a breakdown for Muncy in terms of fastballs in the heart of the plate:

Max Muncy: Heart Fastballs Breakdown

Some context is necessary here, obviously. Muncy has seen about 30% of his fastballs in the heart of the zone, a rate that is among the top 20 highest in baseball this season, and up from 26% in 2019. Muncy also swings at these pitches about 70% of the time, which, while not among the league’s lowest, is a rate that is below the league average of 74%. Additionally, Muncy is seeing more fastballs in the heart of the zone this season compared to 2019 by almost five percent, but seeing more pitches here has not corresponded to more swings in this portion of the zone, as Muncy’s heart fastball swing rate last season was 70.27%, essentially identical to this season’s rate.

Because Muncy is such a patient hitter and already one of the more passive hitters at the plate, it makes sense, in theory, for Muncy to lag behind the leaders in terms of swing rate, even on pitches in the part of the zone where hitters should be doing most of their work. Remember though, that I said Muncy’s elite plate discipline may be holding him back. One thing I wanted to check was how Muncy fared in some of these same areas as some of the league’s other top walkers. If our theory is correct, the other top walkers in the league should have pretty similar rates in this regard to Muncy. In actuality, that is not exactly the case:

Top Walkers: Fastball Swing %

While we know that Muncy gets one of the lowest rates of fastballs in all of baseball, it is still the case among the hitters with the top walk rates this season, a group that includes some pretty good hitters. While a lot of the hitters in this table have low fastball swing rates compared to the rest of the league, Muncy is among the most passive, especially so when looking at swings at fastballs in the heart of the strike zone. Despite Muncy seeing among the most pitches of this type, he is one of the lowest swingers in this group. For the most part, the hitters in this group, despite already being pretty infrequent swingers on fastballs, know to jump on the mistakes in the heart of the zone. It goes back to the idea that Muncy may actually be too passive on pitches here, especially when considering how much he is struggling against non-fastballs. Muncy’s overall passivity on pitches in the heart of the plate may also explain why Muncy is among the bottom of hitters in terms of Statcast’s swing and take leaderboard on pitches in the heart of the zone. More specifically, in terms of overall take runs in the heart of the zone, Muncy has negative five of them, one of the overall league-worst:

So, is the answer just that simple and that Muncy should be more aggressive on fastballs and all will be golden? While it’s probably not that easy , I think he would be better off swinging at more fastballs, especially considering how many he is seeing in the heart of the zone and his struggles against the other pitches. It may require him to change up his game plan at the plate a bit and be less patient overall, but other patient hitters are swinging at a higher rate of fastballs than Muncy and are still able to maintain their overall strong discipline, so perhaps it can work out for Muncy.

While this won’t save his season by any means, with there being too little time (one of the major downsides of a 60-game season), pitchers will likely continue to attack Muncy in this fashion with fewer fastballs in the future. Muncy should try to make them pay more for the ones that he does get and capitalize on them by swinging at more of them and continuing to get the solid results on them that he does get instead of letting a lot of them go by.

(Photo by Chris Williams/Icon Sportswire)

Matt Wallach

Matt studied accounting at UAlbany, is a Yankee fan, and writes for Pitcher List and Rotoballer where he can work with even more numbers to analyze baseball players, which is a lot more fun.

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