Why Your Favorite Pitcher Isn't Merrill Kelly

Brent Strom isn't walking out of your dugout...

It’s April, which means it’s time for small sample sizes in baseball. At this point, it’s basically a cliche to talk about why so-and-so’s hot start isn’t real, and I know I like to talk about randomness on here, so I’ll leave that one for another day.

What I also think about a lot is a throwaway line from an NFL podcast I listened to some months ago. The gist of it is that it’s actually a competitive advantage to play your best players more often. This seems obvious, but it’s a competitive advantage because not all coaches do so.

Sometimes you’ve got the first-round pick who clearly doesn’t put in the work, while the fourth-rounder at the same position is willing to step up. Sometimes the vet can’t hang with the young guy. Sometimes the guy on a vet minimum is better suited than the guy on a massive deal. Regardless, the more often you play your best players, the more often you’re going to win football games. Cam Newton might have been a vet, and Mac Jones a rookie, but Bill Belichick knew who was going to win him more football games, and so he released Cam right before the season. Mac Jones took them to the playoffs.

This also translates to pitchers in major league baseball. Every pitcher has multiple pitches that they can throw. Some only throw two, while many throw four or so, and Yu Darvish throws something like eleven. There are a few types of fastballs (four-seam, two-seam, sinker), a few types of breaking pitches (slider, curve, change), and some in between (the cutter is a good example of this). Each pitcher throws at their own speed, but it’s likely that the four-seam will be the fastest, the slider will be faster than the curveball, etc.

Some pitchers are harder to hit than others. The first major breakthrough of 21st-century advanced baseball stats was the idea that a pitcher has no control over what’ll happen to a baseball after it’s been hit. More recent research has found that to not be entirely true, but the point remains: now, more than ever, pitchers are focused on getting guys out without them ever landing a ball in play.

So you’d think they’d focus on throwing their best swing-and-miss pitches, right? Wrong. The linked article shows that, of the 92 pitchers who threw at least 2,000 pitches in 2021, 64 have a negative correlation between pitch usage and swinging strike percentage (or SwStr%) on those pitches. This is, I should mention, partially for an important reason. The most common tool in a pitcher’s arsenal is their fastball, and those aren’t necessarily strikeout pitches. As Ben Perry mentions in the article, those with the highest positive correlations (i.e., they throw their whiff-inducing pitches most often) are those with fastballs that induce whiffs at a higher rate than normal.

The point, though, isn’t that you’re outta luck if your fastball isn’t your best pitch. It’s that, all over baseball, there is so much ground to be gained. All over the sport, players are pounding inefficient pitch after inefficient pitch, and it’s hurting their bottom line. That’s where Brent Strom comes in.

For most of the past decade, Brent Strom was the pitching coach for the Houston Astros. Every pitcher who has joined the Astros has become considerably better upon working with him; no, seriously, it's really true. Justin Verlander and Gerrit Cole reached points they’d never gotten to before, Ryan Pressly became one of the best closers in the game, Collin McHugh had the career no one thought remotely possible, and people forget how bad Dallas Keuchel was before Strom moseyed along.

But Charlie Morton is the shining star. In essence, Strom told the 33-year-old with a very short history of success (and a long injury history) to start anew. “Fuck ground balls; let’s strike guys out” was Strom’s mantra. As detailed in the article, it was tough for Morton to adapt to this, but at some point, he decided to “just let it rip,” and suddenly he was throwing 97 for the first time in his life. That’s the Brent Strom secret sauce: throw your best pitches, and throw ‘em as hard as you can.

Strom retired this past fall, or at least for a couple weeks. The pitiful Diamondbacks plucked him out of Tucson and lured him to Phoenix, where the 73-year-old can still live a mostly-retired life. Before this season started, I wanted to look for early returns from DBacks pitchers, trying to find out who’d taken Strom’s words to heart. It’s early, but I think I’ve got one.

Merrill Kelly bounced around the Tampa Bay Rays for a while, never really making it as the starter he thought he deserved to be. So he did what most people don’t, and went to Korea for four years. Upon his return in 2019, he signed with Arizona, and in his two full seasons (2019 and 2021), he was basically a league-average pitcher, with a 4.42 ERA and 103 FIP- in 2019, and a 4.44 ERA and 98 FIP- in 2021. He struck out about 7.5 guys per 9 innings, or a K% of about 20%, neither all that great. He was an innings-eater on the other side of 30, and that’s about all he was expected to be.

And then he started pitching this year, and all his pitches are about 1.5 MPH faster than they ever used to be. His fastball is still his most common pitch, but he’s suddenly throwing his changeup more often than any other pitch. And it isn’t any old changeup. Last year, his changeup had induced more whiffs (27.4% of the time) than any pitch in his arsenal, but he threw his sinker and curve more often. This year, through two starts, that changeup is inducing whiffs at a 43.5% rate. He’s throwing it harder, its spin rate is significantly up, and it’s breaking a couple extra inches both horizontally and vertically. The two Strom rules: throw your best pitches, and throw ‘em as hard as you can.

Through two games, both against teams with great offenses, Kelly has pitched 9.1 innings, allowed 7 hits and 2 walks, and struck out 13 batters. He also hasn’t allowed a run. It remains to be seen whether Kelly is the only guy on the team to take Strom’s words to heart, as their best pitcher, Zac Gallen, hasn’t pitched yet due to sticking his finger into an electrical box.

I’m optimistic, though. If you’re looking for the next guy, DBacks reliever Kyle Nelson has only pitched in two games, but he’s basically ditched his cutter, added two MPH to his slider, and has struck out four out of the nine batters he’s faced in 2.2 scoreless innings. It’s early yet. Check out the Baseball Savant page of a struggling pitcher on your favorite team, and by now you know how to see if he might just benefit from a visit from good ol’ Brent Strom.