Visualizing and Quantifying Pitchability, with Simeon Woods Richardson

It won't be like this all year. Simeon Woods Richardson is not a true-talent 2.57 ERA pitcher in MLB, and his strong showing since joining the Twins rotation is due for some measure of regression. However, the success he's had isn't unearned. He's made material changes since last season, and he's crafted a versatile arsenal--partially by making two of the pitches within that mix versatile in and of themselves.

After tweaking his mechanics this winter to unlock his former velocity and be more athletic throughout his delivery, Woods Richardson has established a four-pitch repertoire this spring: four-seam fastball, slider, changeup, and curveball. Neither the changeup nor the curve is especially effective, though, so his fastball and slider need to do a lot of different things. It's hard to have lasting success as a starter with two pitches driving the bus; you need the ability to manipulate those offerings.

Thankfully, then, Woods Richardson has fostered just that kind of flexibility this year. Here's the movement chart for all of his offerings for the season to date:

It's hard, at a glance, to see what makes this unique, so firstly, let's compare Woods Richardson to one of his teammates. Here's the same chart for Twins starter Bailey Ober.

In analyzing pitch movement, the default tends to be to study the average of all pitches of a given type. How much does that offering typically move, and in which direction(s)? Our brains aren't supercomputers, so to break these things down, we try to take a single number. The average is the intuitive one to use.

When you look at the charts above, though, something should jump out right away: the shape of the distribution of movement is different, and the size of the spread for each is different. Ober has a tight cluster of fastballs; his heaters all move relatively similarly. Woods Richardson, by contrast, has a big spread--but only in one direction. The band of vertical movement he gets on his heaters is pretty small, but the band of horizontal movement is quite wide.

This actually is something we can measure, and relatively easily; it's just not often taken into account. Here are all the pitchers who have thrown at least 200 four-seam fastballs so far in 2024, plotted based on the range of movement they show on those pitches, both horizontally and vertically. (The range, here, is defined as the difference between their 90th-percentile movement in that dimension and their 10th-percentile movement in it.)

This isn't a set of data in which you necessarily want to have as small or as big a number as possible. Were we examining the standard deviation of movement, we'd probably view smaller values as better ones, because that might stand in for command, but that's not what we're doing here, exactly. Rather, we're seeing how far a pitcher can stretch and move their movement in each dimension.

As you can see, Woods Richardson has one of the largest horizontal movement ranges in the sport, but a below-average vertical range. While it's not clear in all cases how these numbers reflect value, for Woods Richardson, that's a clearly positive thing. Why? Because he pitches like this:

That's not as dramatic an overhand delivery as Woods Richardson used last year, when he was interfering with his own arm strength and cutting the ball at under 90 miles per hour, but it's still a high arm slot. Based on throwing that way, we would normally expect his errors--the balls that don't move the way he wants them to--to be in the vertical dimension. In other words, when he gives the pitch more lateral movement from one offering to the next, he's not just missing. He's manipulating the pitch, to attack different parts of the zone and/or give hitters different looks.

Here's Woods Richardson's movement chart for last season's stint with the Twins. Again, you can see that dramatically different average movement profile, but you can also see less of a scatter--less maneuverability with the fastball.

Now, let's talk about the slider. That pitch has significant two-plane separation from the fastball, but it also has a different orientation in terms of the spray of its movements. This time, compares to the average hurler, he has a greater vertical movement range, but a smaller horizontal one.

Obviously, in keeping with the above, this indicates more difficulty with command, and the risk is that it means leaving too many sliders up; those might get crushed. However, a pitcher who needs to attack hitters two or three times within a game needs the ability to do more than one thing with their breaking ball. Woods Richardson has to be able to throw the slider for a strike (strike to strike, starting out looking like a high fastball and ending up low in the zone), for chases (strike to ball, diving below the zone), and to steal called strikes (ball to strike, dropping into the zone unexpectedly). Thus, the ability to change how much vertical movement a pitch gets from one to the next is important to Woods Richardson, and he's demonstrating that valuable skill.

Again, he's going to give up more runs at some point. He's going to hang a slider or two, and he's going to miss out over the plate with a fastball meant for a corner. His ERA is more likely to start with a 4, the rest of the way, than to start with a 2. Still, this is pitchability in a nutshell. Woods Richardson is young, but he's also mature, thoughtful, and talented. This year, he's getting a chance to show it, and he's seized that opportunity so far.