By the Way, Jose Alvarado Was Impossible

Let me explain how I landed on Jose Alvarado. Alvarado is a reliever for the Rays. I actually wrote about him last June, but not because of his pitching.

Right. So why Alvarado, on today of all days? It’s not like he’s been showing up in trade rumors. Here’s the explanation: I’m a guy who loves looking at bullpens. I was also looking at the Twins last night, considering them as a possible sleeper. One guy they should be getting back is Michael Pineda. Another guy they already got back is Trevor May. May is going to pitch out of the Minnesota bullpen, and when he returned in 2018, he put up some encouraging numbers. I went into the leaderboards, to see how his numbers stacked up. That’s where I came across Alvarado. That’s what prompted all of this work.

Almost completely off the radar, Alvarado broke out late in the season. There’s no need to be complicated here. This is a very simple table:

That’s a list of some talented pitchers. Down the stretch, Alvarado struck out almost literally half of his opponents. He struck out the same rate of opponents as Edwin Diaz. I’ve written before about Ryan Pressly’s breakout. I’ve written before about Jose Leclerc’s breakout. What happened with Alvarado? Did anything happen with Alvarado? The answer is yes. He changed on the fly, and became something dominant.

Let’s be clear about something: Alvarado was already obviously gifted. Even today he’s just 23 years old, and when he debuted in the majors in 2017, he threw his average fastball more than 98 miles per hour. It’s easy to shrug and say something like “sure, but nowadays everyone throws 98 miles per hour,” but pitchers like Alvarado remain a rare breed. It’s not just anyone who can brush triple digits. Alvarado’s initial season was a good one. He made a strong impression.

But he wasn’t what he was down the stretch in 2018. That was a different pitcher entirely. Consider the following plot, again showing last August and September. On the y-axis, you see ground-ball rate. On the x-axis, you see K-BB%. Alvarado is the point in yellow.

The point right next to Alvarado is Pressly. And there’s no one else nearby. A ground ball isn’t necessarily better than a fly ball, since a fly ball can be a pop-up, but traditionally, the three pillars of success are high strikeouts, low walks, and low homers. You can’t easily hit a homer on the ground. Over the season’s final couple months, Alvarado was close to statistically perfect. I’ll show you another plot below.

Here’s one showing actual wOBA and Statcast’s expected wOBA. Alvarado, again, is the yellow dot. You want to be low and toward the left. That’s where all of the great pitchers are.

What’s clear, beyond a shadow of a doubt: Late in the season, Alvarado was one of the best per-inning pitchers in baseball. What’s less clear is how it happened. But this is always the more interesting part — the part of exploring the why. Yes, Alvarado throws his fastball in the upper-90s, and that gives him a natural advantage. There were changes, however, which allowed him to become a more optimized version of himself.

Just to choose a starting point, Alvarado in 2018 altered his arm action. You see two images below, one from April and one from September. Over the course of the year, Alvarado changed his release point to become extremely over-the-top. You see his release almost directly above his right foot.

Changing one’s release is one thing. When you change your arm angle, you change the angles by which you attack opponents, and you change the movement of your pitches. Yet there was also a corresponding change in the pitches that Alvarado threw. I’m now going to use some images from Texas Leaguers. Here’s a plot of velocity against spin angle. On the left, Alvarado’s season through July. On the right, his final couple months.

Something new shows up in the middle. You also see a change with the fastballs. I think this can be supplemented by looking at side-by-side plots of pitch movement.

Here’s what happened, beyond just the arm-angle change. In 2017, the Rays sent Alvarado to the minors, in large part to work on a two-seam fastball and a cutter. Before, he exclusively threw a four-seam fastball and a curveball. Earlier in 2018, Alvarado threw both fastballs, and he leaned somewhat heavily on his curve. Later on, though, almost all of his fastballs were of the two-seam variety. And the curveball was largely replaced by harder cutters. Compared to the curve, the cutter has similar horizontal break, but it trades some vertical break for velocity. I’d say there’s no arguing with the results. The hazards of examining small samples are ever-present, but the two-seam/cutter combination allowed Alvarado to reach some new heights.

The cutter is commonly 88-91. This is what it looks like when it makes a fool of Aaron Judge:

And the fastball is the fastball. When you can throw your fastball in the upper-90s, it sticks in a hitter’s head. When that hitter knows you can also throw something softer, it makes a fastball look all the more fast. This is a fastball from later in the same at-bat against Judge:

From August 1 through the end of the season, Alvarado faced 75 hitters. He allowed nine hits, with six walks and 35 strikeouts. He’s a reliever, so he’s volatile, and it’s a small sample, so it’s unreliable. But then, you’d think a guy with Alvarado’s repertoire would be difficult to hit, and he seems to have really taken a liking to his new cutter. It would appear that it pairs well with the two-seamer, and remember that, in 2017, it was Blake Snell of the Rays who had his own late-season breakout. He carried that over into a Cy Young award. No two pitchers are alike, and Snell broke out over a greater number of innings, but all the evidence for Alvarado is there. His improvement was driven by changes, and he possesses a special arm.

As I’ve evaluated the Rays, I’ve thought they were still short a quality high-leverage reliever. Indeed, perhaps they still are. The richest teams, after all, are loading up. The Rays would benefit from adding another good reliever, but in my evaluations, I’d overlooked what Alvarado did. Alvarado already became what the Rays might be looking for. Now he just needs to sustain it. Score one for the player-development system.