Approaching the Beginning of a Plate Appearance (1/n)

In my last post I talked about throwing pitches out of the zone in 0-2 counts. I concluded that it was an effective strategy because of the increased chance of a putaway and the cost of going from an 0-2 to 1-2 count was small from the perspective of the pitcher. If the batter takes the pitch, the pitcher maintains the advantage in the plate appearance. Plate appearances that reach a 1-2 count still result in strikeouts 39.9 percent of the time and a 0.243 wOBA compared to 46.2 percent and a 0.217 wOBA in 0-2 in plate appearances reaching an 0-2 count (based on 2020 data).

Now I am going to flip this analysis around and look at approaching the beginning of a plate appearance (from the pitcher's perspective). Investigating waste 0-2 waste pitches was of interest because of their controversial nature when talking about or watching baseball. But we saw how the decision to throw a pitch of this nature lacked import, in that the pitcher still had all of the leverage if the batter takes the pitch. The beginning of a plate appearance (I looked at the first three pitches) is another animal. The advantage for either the pitcher or batter swings wildly with these three pitches. Let us first look at the first pitch. The average OPS in the 2020 season was 0.740. After an 1-0 count that increased by 92 points to 0.832. For an 0-1 count the figure dropped by 118 points to 0.622. For context the difference between 1-2 and 0-2 counts was 50 points. If you consider leverage the potential swing in plate appearance outcomes in terms of OPS/wOBA, you would say there is about twice the leverage in the first pitch as there is in an 0-2 pitch (neglecting outcomes involving plate appearances ending which obviously have the most drastic OPS/wOBA swings). Here is another example: after an 1-0 count the league average OPS is 0.832 (cited above). That swings to 0.995 after a ball (163 points) and 0.679 after a strike (153 points). These early pitch outcomes are crucial to understanding how a trip to the plate plays out. 

This is going to be one of (hopefully) a series of posts about how pitchers approach plate appearances including (but not limited to) sequences of pitch types and locations and their effectiveness relative to one another. I ultimately want to look at macro trends and how different groups of pitchers solve this puzzle. Before undergoing this type of analysis I had to first figure out ways to manipulate the pitch data to answer these questions. Thus, I am focusing on one player for now and then plan to apply the necessary techniques to the league at large. I chose the best pitcher on the team I most closely: Gerrit Cole. 

Cole unsurprisingly yields better results (like the rest of the league) when he throws a first pitch strike. 

Cole gets first pitch strikes on balls not put into play about 60 percent of the time which is just about league average. Plate appearances that start with a strike are about 30 percent more effective, also in line with the league-wide splits I cited above. The 23 balls in play on the first pitch against Cole he gave up a 0.529 wOBA compared to the league average of 0.383. Cole has never been a standout in limiting damage on contact (to the extent that pitchers actually control it). His elite repertoire makes him not fear challenging the hitter in the strike zone. His approach has merit supported by his results in Houston and New York. The downside to attacking the zone is when hitters make contact his results may go awry. Keep in mind that we are looking at just 23 batted balls. I would not expect this phenomenon to persist in the future. 

Cole is extremely effective picking up first pitch strikes with his slider and the results with is curveball fall way behind. In 2021 if he wants to continue to be aggressive throwing his curveball to start a plate appearance he needs to be more efficient either by throwing the pitch in the zone or inducing swings and misses. Batters often let first pitch breaking pitches go by so the former approach may be the better option. 

Naturally let us look at the second pitch and account for the pitch type he threw on the first pitch. The sequences are coded so that the pitch to the left of the dash is the second pitch. 

The red dashed line in each panel represents Cole's average wOBA allowed overall so points below the line are better. Cole has better results on contact when throwing his fastball twice in a row. When leaning on his slider Cole was excellent which speaks to the pitches quality in 2020. He had trouble with his curveball no matter the sequence. He did not throw his changeup enough to come to any firm conclusions but he mainly uses it when he is facing a platoon disadvantage so to be effective in that sample is positive. But the sample is small so I am reticent to make bold proclamations. 

Finally a similar visualization but with sequences for Cole's first three pitches to the batter.

There is a lot going on here so I will let you look over the panels on your own but I will make a few comments. Cole starts hitters with three straight fastballs frequently. Sequences involving at least two fastballs generally performed well which speaks to how tough his fastball is on hitters (despite the fact that hitters generally perform better on fastballs). The curveball worked well following his other pitches. That is not to say he suddenly got control over the pitch when sequencing it with others but I would imagine he does not mind throwing it outside the zone in favorable counts and it tunnels especially well off of his 98 percent active spin fastball (which means its vertical movement is top notch).

There is nothing predicative about these results. The 2020 season was short and I looked at one pitcher. When I eventually look at more pitchers and the league as a whole hopefully I can yield some more interesting insights on the best methods for attacking hitters to mitigate wOBA against. I did not consider the counts in which these sequences were thrown which I will do in the future. The issue here was I am looking at one pitcher in a shortened season so I thought I would be slicing the data too finely (if I was not already).

OPS count splits via data reference and pitch level data acquired via MLBAM