Brad Keller and the Terrible, Horrible, No Good, Very Bad Fastball

The big Royals righty had a rough year and the fastball was the reason.

As far as Rule 5 picks go, Brad Keller has been the second most successful in team history behind Joakim Soria, at least by Wins Above Replacement on Fangraphs. He made the team in 2018 and was so good out of the bullpen that the Royals gave him a shot in the rotation. He was good enough there that he was the Opening Day starter in 2019. Okay, maybe it wasn’t so much how good he was but how bad the rest of the team was, but he still had a solid year with a 4.19 ERA in 28 starts. And he had what was his best season in 2020, albeit in a shortened year. And now that we’re sufficiently caught up on Keller before 2021, let’s get to the struggles.

It started almost immediately. After allowing two doubles all season in 2020, he allowed three to the first five batters against the Rangers and put the Royals in a 5-0 hole before they even came to the plate. Michael A. Taylor’s arm pretty much saved him and he just never got on track. There were times when he looked better and then he’d fall back into a bad stretch. On the bright side, he did turn things around a bit after a start in Boston when Keller probably said the quiet part out loud and mentioned that Cal Eldred and the Royals pitching staff were able to pinpoint some issues because of the Fenway Park camera. But that’s another story for another day.

From that point to his start before his last one that he left with a shoulder issue, Keller averaged six innings per start, had a 24.8 percent strikeout rate and 8.9 percent walk rate with a 48.5 percent ground ball rate. Forget any other number, those three stats working together will get the job done. He had a similarly solid stretch a few weeks earlier in an eight-start stretch where he posted a 3.71 ERA with a 21.8 percent strikeout rate, 8.3 percent walk rate and 48.1 percent ground ball rate. The difference between the two stretches is that he was getting hit hard the first time, allowing a .279/.342/.459 line and average exit velocity of 93 MPH compared to .239/.313/.350 with an average exit velocity allowed of 88.2 MPH. That’s much better.

But all that said, there was a consistent issue throughout his season and it was his fastball, which was an absolute disaster. And pretty much no matter how you looked at that pitch, it was his biggest problem. By pure results, he gave up a .325 average and .510 slugging percentage on the pitch. Compare that to .179/.269 in 2020, .260/.409 in 2019 and .272/.366 in 2018 and it was significantly different. His fastball had a run value of 18 in 2021. That seems like it might be good on the surface, but run value for pitchers looks at the change in value each pitch provides, so a positive run value for a pitcher is a bad thing. It was the third worst pitch in baseball behind only Jake Arrieta’s sinker and Zach Davies’ sinker.

His fastball was tied for 376th out of 424 in terms of vertical movement compared to league average and 420th out of 424 in terms of horizontal movement compared to league average. While his spin rate was generally fine on it (2,322 rpms ranked 240th out of 753 pitchers who threw at least 50 fastballs), his active spin was…not fine. His active spin of 69.3 percent ranked 631st. What that means is that while he was spinning it adequately or maybe even better than adequately, the amount of spin that contributed to movement was just low. So basically the guy is throwing a ball 94 MPH, but it’s barely moving. Big league hitters can do just fine against that.

So it’s pretty clear what the issue was. My question that I don’t know the answer to as I type this is if his fastball had the same issues in previous seasons when it was a much more effective pitch. Looking at the surface numbers, by spin rate, it’s been pretty similar. By extension, it’s been within 0.1 in all four years of his career. By velocity, he actually saw a pretty big drop in 2020 and saw that jump back up in 2021, so that’s sort of interesting. But what about when we dig into movement.

In 2018, it dropped a bit more, but didn’t move horizontally any differently. His active spin was basically the same as in 2021.

In 2019, the vertical movement was about the same and his horizontal movement was even less. His active spin was even less than in 2021.

And in 2020, the pitch dropped quite a bit more and it moved horizontally quite a bit more as well. The active spin was down, but the movement was at least there.

Okay, so we’ve learned that the year he had the best results with his four-seam fastball was the year it moved the most. Seems pretty obvious here, but there’s probably more to it.

One explanation was brought up in an article by Alec Lewis early in spring training in The Athletic. It was all about seam-shifted wake. If you take a look at the image below, you can see the spin-based movement on the left from 2020 and the observed movement on the right.

You’ll see it’s a different view. It’s not drastic by any stretch, but while the spin indicates the fastball is going way, it was going another way. We’re not really talking about his other pitches here, but they play into it, so you can see his slider moving more vertically in the observed spin and his sinker moving way more arm-side. And on that four-seamer, you see that while the spin indicates it’s more arm-side, it’s actually moving in a way that’s a bit more to the glove-side, almost cutting.

That’s something Freddie Freeman mentioned in the article linked above.

But if you look at 2021, the side-by-side is just a bit different. The pitches are still moving in the same direction compared to the spin-based movement, but it’s not quite as drastic. So the four-seamer, instead of cutting toward the left-handed batters box, is basically just staying pretty straight. Again, that’s not news, we talked about that above, but it’s a different way to look at it.

The difference in the spin-based movement compared to the observed movement was tied for the seventh biggest difference in baseball on four-seamers in 2021. He was right there with Sonny Gray, Logan Webb, Joe Musgrove and others. In 2020, the difference was even more drastic and was second-most in baseball.

I’ve gotten off track because that sort of thing is absolutely fascinating, but the good news here is that I’m thinking a lot of this has to do with his release point, which makes a lot of sense that they were able to see this from the Fenway cameras. Take a look at his release points, by month, throughout his career on the four-seamer.

First, vertical:

Now, horizontal:

This tells me that his vertical release point isn’t quite as important as the horizontal for the movement on his fastball, at least for Keller.

Let’s take a look at a pitch he made in 2020 that I, for some reason, still remember in a blowout against the Pirates. Probably because it was filthy.

Now he obviously made pitches like the one in 2020 in 2021 and like the one in 2021 in 2020. It’s not that every fastball was a disaster last season and every fastball was a gem in 2020, but you can see the ride and the cut on that fastball in 2020. Then this one against the Red Sox just…didn’t do that.

It’s hard to truly see a big difference in release point due to a slightly different depth of camera, but looking at the extension from 2020, I personally see a bit more. And in a true game of inches and even centimeters, where the ball is released can make a very big difference.

You might remember that I found myself worried about his health to start the season. He wasn’t throwing his slider as much and his velocity increased. That doesn’t always mean injury, but it is a potential indicator. So the good news here is that as the season went on, he started using his slider more and more and the fastball less and less. The bad news is that he’s now been shut down early in each of the last two full seasons. I think we’ve seen that his fastball can not only be good but can be dominant because of how he disguises movement with it. I just worry a bit about how long he can maintain throwing his slider as often as he did for July and August. To throw a slider 41.5 percent of the time is an awful lot.

So I have some confidence that he can find the fastball again, but he also has shown that he can be set in a bad direction by very small mechanical flaws. I know that a big-bodied pitcher with his kind of ground ball ability is a weapon in the rotation if he’s pitching well, but I would be very interested to see him back in the bullpen now with the years of experience to help him. Maybe that fastball can sit more in the 96-97 range like it did when he started his career there. Add in the slider in short stints and maybe he’s dominant.

That isn’t where I’d start the 2022 season with him. If he can be the guy we saw in those last couple months or the guy we saw in 2020, he should be out there every fifth day. That said, it’s definitely a thought because if he doesn’t figure out his fastball in 2022, that might be the last resort to extract the most value from him as possible, which would also be good for him as he’s now knocking on the door of free agency. A tough first few months of 2021 has made his 2022 very important and the road back to being an extension candidate is to get that fastball figured out.