The second-year slump almost feels like a rite of passage in sports. It can happen for any number of reasons but some are simpler to identify and blame than others. In the case of Gavin Williams, it would be easy to say: “He started the year on IL with elbow inflammation and it’s affecting how he’s pitching this season”. This doesn’t cover everything, however. Especially considering he’s actually throwing harder this year despite the recent elbow trouble. No, he’s changed up his arsenal since his rookie season, but the results have been worse.
That said, not all of the changes are a bad thing. He needed to make some adjustments anyway. To paint a clearer picture of the change, we’ll look at what he was doing last year, and then compare it to this year. From there we can try to determine how much of his struggles are small sample noise, and how much of them are related to the changes he’s made.
The Arsenal
Williams’ fastball in his rookie season was a strong if somewhat generic offering. The movement at his release wasn’t particularly notable but he threw hard and with ridiculous extension helping it to play up. It was a comfortably plus pitch, with the whiff rate and results to match despite just acceptable command and locations.
His slider was his best-performing pitch in 2023. It was a bit surprising actually, a pretty standard gyro slider at 85 mph is usually a good pitch but it significantly outperformed what you’d expect from that. I think his extreme fastball usage played a pretty substantial role in this outcome. When you’re throwing your singular fastball 55% of the time, hitters will take note of that and sit on the fastball. This can allow the secondary pitches to play better than they are due to hitters being focused on the heater. This isn’t to say it was a bad pitch. It was maybe a little on the slow end considering the velocity of his fastball but that didn’t seem to cause any issues with deception, though his ability to locate this pitch down and off the glove side corner certainly didn’t hurt either.
Williams’ curveball had a ton of movement but his inability to zone it and its frankly slow velocity compared to the rest of his arsenal caused problems. It was identifiable due to its big shape and frequently wasn’t in particularly enticing locations. It did have a good spin mirror going for it though. Also, it played well when it was near the zone as all that movement made it hard to hit, but it needed work.
His changeup played poorly and that was a bit surprising to me. Maybe it was that he rode the line of pitching on the edge of the zone as opposed to just off of it too closely but it didn’t get chases and was hit hard in the small sample. The latter I’d expect but the shape was fine and there wasn’t anything about it that screams an issue with not fooling hitters unless he had a tipping problem I’m not noticing. That said he only threw 77 of them, so it could just be a small sample thing. It didn’t have great depth but it cut velocity reasonably well and had good fade. It was worth workshopping in the offseason at least.
So, that was Williams in 2023. A fastball-dominant pitcher with a pair of breaking balls that played up due to his fastball usage. That sounds harsher than I mean it, he was good! As much as I talked about his fastball aiding the slider, it was probably still a 55-grade pitch. Maybe he or his pitching coaches disagreed with this notion, as that pitch no longer exists in his arsenal. Let’s look at what he’s doing this season now that we have the context of what he used to be.
Williams is throwing harder this year, and that’s good! His fastball shape has regressed, however, and that’s not good. He’s releasing the ball on a lower spin axis which is costing it a bit of rise. Ultimately, this is probably a net-neutral change. The whiff rate is a bit lower, which isn’t surprising given the shape change, but it’s also inducing slightly more pitcher-friendly contact. He’s also throwing it higher more consistently, which is promising. The ICR% is down, but the barrel rate is up. I think generally speaking it’s better at managing dangerous contact even if the results are a bit mixed so far. Again, I think this is largely a neutral change and not the cause of his problems.
His curveball has overtaken the slider as his new second-most used pitch, but he’s throwing it much harder this year. He still doesn’t zone it much but he’s gotten good at locating it below the zone and is running an 86th percentile chase rate with it as a result. The lack of strikes is less than ideal but this pitch is doing its job. He throws it with two strikes with the intent of ending the at-bat, and it does so at a solid rate.
He added a cutter over the offseason, and it’s excellent. It functions as a slider/cutter hybrid, capable of getting whiffs with the speed and spin direction of a cutter to make it look more like a fastball out of the hand. This is a great addition, and it’s exactly what he needed to round out his arsenal.
His slider has unfortunately regressed since last year. He’s throwing it harder, but it lost a lot of depth and has turned into a less good version of his new cutter. It also serves as an inferior bridge between his fastball and curveball, a job the older slider did well. This could be an unintentional result of adding the cutter and the pitches starting to blend, but the old version is gone entirely. This makes me think it might be a conscious choice, one he should undo. The new cutter compliments the old slider well, but it makes the new slider worse by essentially being a better version of it. It’s also possible they believe his old slider was causing his elbow problems, in which case the change is necessary, though unfortunate. This new one gets some called strikes for him, which is an area he’s generally lacking in, but it comes at the cost of getting hit hard when they don’t let it go by.
His changeup didn’t change much. As he dropped his arm slot slightly, the changeup saw similar movement changes as his fastball. This is what you would expect to happen. It’s functionally the same as any of its potential is relative to how it plays off of the fastball, and as they have the same relationship they did last year, there’s not much to note.
What Does All This Mean?
So we’ve established the changes he made. He dropped his arm slot a bit, causing his pitch shapes to get a bit more east-west, which hurts the whiff potential. However, he has filled the gap by throwing harder. He also scrapped his old slider in favor of a new cutter. In terms of process and stuff, I would say he should be pitching slightly better than he was last season. His arsenal is probably a touch improved this year, which is not what I was expecting to find when I started looking into it. This leads me to what is simultaneously the most boring and most promising diagnosis for Williams’ struggles this season: He’s been unlucky in a small sample of starts. That’s really about it.
Most of his expected numbers are about the same or improved from last season. There’s no reason to panic about his struggles this year. He got better results than his expected stats last year, and fortune swung the other way this time around. Sure there are more changes he could make to improve, he should throw the new cutter more, and bring the older slider back if he can. Maybe work on the changeup command and throw the fastball inside to righties. But at present, Williams is already a decent pitcher, he’s just on a cold stretch.
He has allowed harder contact this year, which is odd considering the new pitch shapes. I again think a lot of this is year-to-year variance. The barrel rate is up, but the solid contact (slightly less than a barrel) rate is down. Both are still lower than the league average. I wasn’t intending to have this turn into a long explanation of the changes he made only for it to end with Occam’s razor. It feels too simple to just say a pitcher is having a tough year, but when all of the more complex potential answers don’t add up, what are we left with? I assumed the changes he made would have had a significant effect on who he was as a pitcher. This is not what happened.
Despite all of his pitches being a bit different and the addition of a new pitch, his expected outcomes are pretty similar. Any little deficiencies that have popped up for him this season that could be attributed to the changes he made should theoretically be made up for by the little boosts he’s seen too. It hasn’t played out that way, but now is not the time to sell all shares and abandon ship. I firmly believe things will balance back out next year barring substantial changes and/or injury of course. As stated previously, I’d love to see him continue to evolve, but it wouldn’t come out of necessity. This current version of Williams is probably a league-average arm with plus stuff. That’s a good spot to be in for a pitcher only three years removed from being drafted.