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Mixing It Up for Fantasy Baseball: Reese Olson's changeup, Luis Severino's sweeper and more

Even though spring training has wrapped up, that's no reason for us to stop looking into pitchers who are throwing new pitches. In fact, this is when the fun begins. Many pitchers will test new pitches in the spring but abandon them when the regular season starts. It can often be more informative to see which pitchers have drastically changed their pitch mix or pitch shape after a few starts in the regular season.

With that in mind, we will continue with the premise of the series I had called Pitchers with New Pitches (and Should We Care) by breaking down notable changes in a pitcher's pitch mix (hence "Mixing" it up). We'll look at pitchers who are throwing a new pitch, have eliminated a pitch or are showcasing a different shape/velocity on a pitch.

I'll continue my analysis with the simple premise that not every new pitch should be greeted with praise. A new pitch, like a shiny new toy, might be exciting on its own, but it also needs to complement what a pitcher already has and fill a meaningful void in his current pitch mix. We want to check and see if he has any splits issues. We want to see what his best pitch(es) is and see if this new pitch would complement that. Then we want to see what this new pitch type is generally used for (control, called strikes, etc.) and see if that is something this pitcher needs help with. We can also now see the pitch in action to look at the shape and command and see if it's actually any good. Once we've done all that, we can decide if the pitch is a good addition or not.

If you missed any of the previous editions of this series, you can click this link here to be taken to the tracker, which I'll update as the season goes on. It will also include links to the original articles so you can read them in full if you'd like.

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I was pretty high on Reese Olson coming into the year and put him in my article about starting pitchers going undrafted who could be in the top 25 by season’s end.

In that article, I mentioned that his fastball is his worst pitch: "Olson throws the pitch around 95 mph, which is fine, but he gets just six feet of extension and 14 inches of iVB, both of which are below average. As a result, the pitch grades out poorly by Stuff+ and PLV. The four-seam doesn’t miss bats with just a 6.6% SwStr% but it also didn’t allow much hard contact to righties with just a 30% ICR. It had a 54% ICR to lefties, which is certainly an issue, but with the other pitches in his arsenal, he likely doesn’t need to keep throwing the four-seamer 43% of the time to lefties."

Reese Olson headshot
Reese Olson
SP - DET - #45
2024 - false season
56.1
IP
1.92
ERA
1.05
WHIP
47
K
19
BB

Instead, what seems to be happening (According to Alex Chamberlain's Pitch Leaderboard) is that Olson has stopped throwing the four-seam to righties, opting for his sinker instead; yet, the sinker is performing worse in 2024, so why might that be?

First, I'm not sure why he dialed back the usage against righties. As I mentioned above, it wasn't a great pitch, but it wasn't hit hard. He kept it glove side often, so the sinker could still work inside. In 2024, the pitch is limiting contact even more against righties but has been better against lefties perhaps because he's using it low more often and it's pairing better with his changeup.

But back to the sinker. This seems to be about location. In 2023, the pitch was good against righties in terms of limiting hard contact and getting groundballs. In 2024, it's getting hit much harder with a 43% Ideal Contact Rate, and I think a big part of that is location. He threw the sinker in the middle of the zone 30% of the time in 2023 but is throwing it there 39% this year. I'd love him to get it up-and-in or low-and-in more often. I know many pitchers hate throwing sinkers up, so even low-and-in would be preferable and help work with his changeup.

I think that could help fix some of his splits issues against righties. That could help his overall performance since he's made some changes with his changeup usage, throwing it far more to left-handed hitters, which is something I also commented on in the preseason article: "He also has a changeup that boasts an 18% SwStr% and can be effective to both righties and lefties if he can iron out the command of it. The pitch had just a 23% zone rate against lefties last year, producing just a 5% called-strike rate which is, in part, why it allowed over a 50% ICR. By throwing it almost 40% of the time to lefties in two-strike counts, they were able to look for it and sit on it when it started low in the zone since they knew he wouldn’t get it over the plate."

So far in 2024, Olson has almost doubled his called strike rate on the changeup early in the count. He's also throwing the pitch low in the zone 88% of the time this year after throwing it low 77% of the time last year, but he's also significantly upped his "middle" locations when it comes to inside and outside, which means that most of his changeups are middle-low, so they fall out of the strike zone low but not away and low. As such, they've become a bit more enticing to hitters and his two-strike chase rate is 45% after being 31% last year.

VERDICT: POTENTIALLY IMPACTFUL. I appreciate the shift in changeup usage, and it's certainly worked for him so far. I also think the adjustment to using the sinker more to right-handed hitters could be good overall. He just needs to fix the locations on it to see a real impact.

Not much went right for Severino in 2023. He had never posted an ERA worse than 3.39 in a season since he became a full-time starter. He'd never posted a strikeout rate worse than 27.7%, and he had never allowed more than 41% hard contact. He had fully lost his fastball, registering far less vertical break on the pitch, and had turned to the cutter more to compensate.

There were myriad changes he needed to make to get back to his previous level. He had under a 10% SwStr% to lefties last year and had over a 10% barrel rate allowed to both. But early in the 2024 season, he made two big changes: he added a sweeper and started throwing his cutter more to lefties.

Luis Severino headshot
Luis Severino
SP - NYM - #40
2024 - false season
58.2
IP
3.22
ERA
1.16
WHIP
50
K
26
BB

The cutter against lefties has been a good thing. It doesn't miss bats, but he's using it to get in on their hands, throwing it inside to lefties 87% of the time after doing so just 71% of the time last year. He also seems to have better command of the pitch in his second year throwing it, seeing an increase in both his strike rate and zone rate. Using the cutter more would theoretically take away some of the pressure on his four-seam fastball which has actually LOST more vertical break and is giving up an ICR of 44% overall and 48% to lefties. It's probably not a pitch he should be using against lefties as often as he does; however, Severino has been dialing BACK the cutter usage and threw just three against the Giants on Tuesday.

So while he's been performing well against lefties, he's really only using three pitches with the cutter, a below-average fastball and a poor changeup that also has a 50% ICR to lefties. If you take the cutter out of that equation, it becomes scary.

Against righties, Severino has turned to his new sweeper 11.3% of the time. The pitch grades out well with 14.5 inches of horizontal movement and four inches of drop at 85.5 mph. However, against righties, it has just a 3.8% SwStr%, even though it is only allowing a 33% ICR. A big part of that could be location. He's throwing his sweeper up in the zone 33% of the time, which is almost double the league average on sweepers to righties. He also seems to have trouble commanding it with just a 35% zone rate.

Without much faith in the sweeper, he's going to his slider more often against righties than he did last year, but he also throws that pitch in the zone just 35% of the time and has just a 10% SwStr%. That's kind of par for the course with his secondary pitches and, even in this performance against the Giants that everybody was tweeting about, Severino had a 28% CSW and just three whiffs on 27 non-fastballs. That's not good.

In truth, the surface-level results are there, but even digging into Severino's changes here, nothing suggests this level of production will continue. Now may be the time to sell.

VERDICT: MINIMALLY IMPACTFUL. Using the cutter more to lefties is good, but it's his only good pitch to lefties since he still hasn't fixed his four-seam fastball. The velocity is there, but the movement isn't back and it's getting hit hard. The sweeper theoretically should miss bats against righties, but he can't command it in the zone and is throwing it up, which doesn't make much sense and is likely not his intended location. I'm really not buying into what he's doing and if you can trade him to somebody, that might be the best path.

In a preseason article on pitchers who made second-half changes, I covered that Lugo came into 2023 and split his breaking ball into two with clear differentiations between the slider and curve: "As the season went on, he started to morph his slider into more of a sweeper. By September, he was throwing an 86.3 mph slider with just 5.7 inches of horizontal movement and an 81.3 mph sweeper with 16.8 inches of horizontal movement. That sweeper had just a 12.1% SwStr% in the second half, so while it was an improvement from the slider, it wasn’t tremendous as a swing-and-miss pitch. However, it didn’t allow a lot of hard contact, and it allowed the harder slider to improve as well, giving up just a 4.8% barrel rate in the second half after allowing a 10% mark in the first half."

Well, now it seems he's taken the same concept and applied it to his curveball, throwing two different ones based on whether or not he's facing a righty or lefty. To righties, the pitch is 78 mph with 11 inches of drop and 17 inches of sweep. To lefties, the pitch is also 78 mph, but it has 18 inches of drop and 15 inches of sweep. That vertical shape against lefties is to help reduce the natural splits of pitches like sweepers, that move into the hot zone of opposite-handed hitters.

Seth Lugo headshot
Seth Lugo
SP - KC - #67
2024 - false season
72.1
IP
1.74
ERA
0.97
WHIP
61
K
15
BB

Statcast has started to differentiate these as his "curve" and his newer "slurve," which is the sweepier version he uses to righties. While I don't think this is the most accurate way to separate the pitches and label them, you can see from the chart how much he's narrowing the gap in terms of his use of each version.

Overall, the curve has been slightly less effective to lefties, allowing a .222 average but a 38.5% ICR and just an 8.3% SwStr%. Meanwhile, the version he throws to righties has a 33% ICR and 11.4% SwStr%. He throws the pitch in the zone less to righties, but it has a much higher chase rate potentially due to the added sweep or the way it pairs with his sweeper and slider. Still, considering the way in which altering the shape of the slider helped him last year, I like the idea that Lugo is simply giving himself more options to throw against hitters of each handedness. If you count each curve shape as unique, Lugo now has eight pitches that he can mix and match, which should help to give him a stable floor.

The other change for Lugo is that he has a new cutter which is 91 mph with 10 inches of drop and no horizontal movement, which is unique for a cutter but pairs well with his arsenal. The pitch has a 5.53 PLV rating on Pitcher List, which makes me optimistic about its shape. He's thrown 43 of them on the season and 42 of them are to lefties, so it's pretty clear who he wants to attack with it, even if we have just a small sample size. He’s throwing it primarily when he's ahead in the count — 60% of the time — and is mainly throwing it high and inside, which is why it has yet to allow any hard contact and has only allowed groundballs so far.

This is a good addition for Lugo because, while he did miss more bats against lefties in 2023, he also allowed almost an 11% barrel rate to them, so he needed a pitch to help him give up less hard contact.

VERDICT: MARGINALLY IMPACTFUL. Lugo is not all of a sudden going to become a dynamic fantasy starter, but so far, he's seen his ICR drop to 33.7% and his barrel rate allowed come down to 7.7%. Aside from his last start against the Orioles, he's been consistently mixing and matching his pitch mix to keep hitters off balance and induce as much soft contact as he can. For a pitcher without overwhelming stuff, the more options he has to do that, the better.