Why Was Jake McCarthy Slumping?

A tough stretch to start the season results in demotion for the Diamondbacks outfielder

Jake McCarthy was optioned to Triple-A Reno after last night's game and infielder Emmanuel Rivera was called up to take his place. The Diamondbacks outfielder got off to a poor start this season as his .143/.229/.238, .467 OPS batting line in 70 plate appearances attests.  He walked five times, struck out 12, and had three extra base hits, one double, one triple, and one homer.  Due to the inability to get on base and use his speed this first month he has just two stolen bases and has been caught twice. 

This is a far cry from his production last year when he was arguably the best player on the team in the second half of the season.  For the full 2022 season McCarthy hit .283/.342/.427, .769 OPS and stole 23 bases while getting caught just three times.  So what happened?

So as not to bury the lead, the two simplest reasons are he was seeing more pitches on the edges of the strike zone than almost any other hitter in MLB and he was swinging at them too much. These edge pitches are known as the Shadow Zone on Baseball Savant's attack zones, (based on Statcast data). Those are pitcher's pitches, good enough to be called strikes most of the time, but extremely difficult to square up. At the same time McCarthy was continually  swinging at these pitches early in counts and as expected, doing little damage with them. His 3.14 Pitches Per PA are the lowest of any hitter in MLB (min 50)   

Attack Zones

Baseball Savant

The above image shows the attack zones for pitchers to go after hitters. The sections marked with numbers 11-19 are the Shadow zones. Below table shows the MLB avg for the number of pitches seen in each zone, as well as McCarthy's percentages. The percentage of pitches seen in the shadow zone is the third most in MLB (minimum 100 total pitches seen), while the percentage of pitches seen in the heart of the zone ranks 347th (fewest) out of 364 batters. These numbers are in sharp contrast to last year when he saw 27.4% of pitches in the heart of the zone and just 42.4% in the shadow zone

	Heart	Shadow	Chase	Waste
MLB AVG	26.0%	42.5%	22.9%	8.7%
Jake McCarthy	21.1%	51.4%	21.1%	6.4%

Pitches in the heart of the zone are of course easier to hit and do damage with. The MLB batting average on these pitches is .314, and the slugging percentage is .561. Conversely, the B.A. on Shadow pitches is just .218 and slugging is .328.  Clearly they are tougher to hit. At the same time, when broken out by these attack zones, McCarthy's numbers were still considerably worse than the league average. He hit .091 with a .152 slugging in the Shadow  and just .200 B.A., .360 slug in the heart of the zone. 

Why was McCarthy seeing such a high percentage on the edges?  Part of that is out of his control of course. There is random variance in these events. He was seeing a lot of good pitchers, but so were his teammates. Perhaps through a little bit of bad luck, these pitchers were landing their pitches in the optimal shadow zone a bit more when facing McCarthy.  But luck is only one component here. He was being too aggressive, trying to make things happen, as evidenced by his league low pitches per PA.  He wasn't forcing the pitchers to come back inside the middle of the strike zone. 

Speaking to McCarthy this past Saturday he expressed the desire to be true to who he is, and be aggressive to make things happen while walking the fine line between that and chasing.   Working with the hitting coaches he did not see much difference in his swing from last year. The frustration was clear, but he was not feeling panic. Be sure to listen to the sound cloud below to hear the player's comments in his own words. 

Somewhat ironically perhaps, in this past Sunday's game he was trying to work the count, but struck out looking with the bases loaded. The two called strikes in the at bat were right on the edge of the zone, one on the  inside corner and the one at the very top. It's very unlikely a swing at those pitches gives him a good result. There was always the chance he got the call his way and drew an RBI walk, but it didn't work out in his favor. Then in his next at bat he got a slider in the middle of the plate and turned on it for a home run to right field. 

Unfortunately for McCarthy it was too little too late to stave off a demotion to Triple-A.  In Monday's game he drew a walk in his first at bat, seeing six pitches. But in his next three at bats he grounded out twice and struck out, seeing just nine pitches. The swings were all at pitches on the edge of out of the zone.

Asked  after last night's game if he was concerned with the way McCarthy  was hitting, Torey Lovullo answered in the affirmative, foreshadowing the move.  "Yeah, a little bit. We need [him] to contribute. I think the swing is a little quick. He might be losing a little bit of his foundation in his base. So We gotta get him right."

70 plate appearances is a small sample size. Almost any player can hit anything over such a small sample.  Career .284 hitter Jean Segura is batting .200 in 74 PA.  Perennial MVP candidate Manny Machado is batting .220 and his teammate Juan Soto is batting .198.  I'm not suggesting that McCarthy is as good a hitter as those players, but it's instructive to be reminded how hard this game is and that over short periods of time our perspective can be skewed. 

The odds are that  McCarthy would have started to figure it out sooner or later. But with the team doing everything they can to compete this year, they are not being as patient as they were in some of the recent seasons with struggling players. McCarthy was sent out twice last year, and each time came back a better player. Hopefully he can do the same in 2023.