I'm Cautiously Optimistic About Sean Casey

by EJ Fagan

July 13, 2023

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NOTE: The following comes from EJ Fagan's substack page and is shared with permission.

Please check out EJ's substack page for more great articles.

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Sean Casey will be the new Yankees hitting coach. After some reflection, I think they made a good call.

I’ve been struggled for weeks to articulate my thoughts about Dillon Lawson, but the gist was that his “hit strikes hard” mantra was really harming the Yankees. The Yankees certainly hit the ball hard, but they are one of the worst offenses in the majors. Other than Aaron Judge, the Yankees have had almost no real hitting successes under Lawson. What gives?

I think there are two things going on. First, I think that the Yankees aren’t working counts and taking walks the way they should. There’s a successful model of Three True Outcomes hitting where batters sacrifice batting average for home runs. However, the the third True Outcome is the walk, which allows the team to have runners on base to score on their occasional home runs. The Yankees still hit a lot of home runs, they are 5th in baseball, but are bottom-half in walk rate. That’s not going to work.

But then I think something else is going on. The Yankees have one of the worst batting averages in the majors despite having an above-average strikeout rate. What gives?

Hitting the ball hard can be a good thing in baseball, but not always. When MLB first started publishing exit velocity and launch angle, Rob Arthur produced this scatter plot of expected run values for balls hit at a given exit velocity and launch angle. Purple is bad, orange is good:

What we see here is that hitting the ball harder is great only when the launch angle is in the sweet spot. A hard ground ball or pop up is bad. A lot of line drives don’t benefit from increased exit velocity, since they are either going to be hit at someone or not. There is even a range of exit velocity where you would rather not hit the ball hard, the bloop/infield single band.

There is also a range where hitting the ball harder isn’t any likelier to produce the same outcome; a 430ft home run counts the same as a 390ft one, and a double down the line counts the same as one off the wall.

Arthur summarizes the exit velocity curve with this figure:

I hypothesize* that the Yankees are underperforming because their hitting strategy is to shift their average exit velocity to the right. That strategy will produce a lot of really good events as exit velocities exceed 95 mph, but fewer hits in the 60-75 mph range that a lot of successful MLB players live in. Teams can also probably adjust their defensive strategies by playing fielders farther back, cutting some of the gains out of the highest end.

* I haven’t tested any of my predictions

Will Sean Casey make a difference? I don’t know. Casey was certainly not a “swing at every pitch as hard as possible” major league hitter, but that probably doesn’t tell us much about him as a hitting coach. I remember his name being thrown around as a future MLB manager or hitting coach when he retired, but he chose instead to go into TV. My guess is that he has a reputation among baseball people as a person who would be a solid coach, but the lack of experience is telling.

Maybe the Yankees need some better vibes in the clubhouse. Maybe Casey will have some specific hitting advice. I hope he tries to convince guys like Donaldson, Stanton and Volpe to try not just swinging hard all the time.

I think any change will take weeks to play out, and weeks may be too long for the Yankees.