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Kevin analyzes four hitter fantasy baseball sleepers who are surging for Week 9. Are they breakouts or fake outs? Read his fantasy baseball outlooks and buys/sells.
The search for hidden gems never stops in the world of fantasy sports. For fantasy baseball, it's undoubtedly helpful to detect positive and negative regression with players so you know who you can trust the rest of the season and who you can sell high on to another manager that will bite.
Eight weeks in, there's still a lot of minutia regarding stats to wade through. Buying into the hype early can be easy, but understanding luck can set you apart from the rest of your league.
In this article, I will break down four hot hitters exceeding preseason expectations. We will find out who's real and who isn't between Cal Raleigh, Geraldo Perdomo, Spencer Torkelson, and Kyle Stowers. Now let's get it.
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Cal Raleigh, Seattle Mariners
2025 Stats: .918 OPS, 168 OPS+, 15 HR, 32 RBI, 31 R, 5 SB
Big Dumper! I've got no idea who came up with that nickname, but there may be no better nickname for a catcher who slugs. Raleigh has been a fan favorite in Seattle for years and is reaching a whole new level here in 2025. As a switch hitter, it gives him tremendous value since there's no matchup, and he can't attack.
Raleigh generally hits better from the left side of the plate, posting a .930 OPS as a lefty and an .887 OPS as a righty. 10 of his 15 HR have come from the left side, a bit unsurprising given he's much more likely to face a right-handed pitcher than a southpaw.
Raleigh's plate approach is very similar to what he did in 2024. However, we see a slight drop in strikeout percentage, going from 28 percent to 25.6 percent this season. That three percent mark has almost slid perfectly over to his walk percentage, which has increased from 11.1 percent to 14.8 percent. That walk percentage ranks in the 93rd percentile and helps ensure he's finding as many ways as possible to get on base consistently.
Cal Raleigh erases the @Mariners deficit with his 16th home run! pic.twitter.com/mlOloamJTL
— MLB (@MLB) May 21, 2025
From a batted ball profile, we can see he's hitting around the same number of fly balls as last year. We see a five percent drop in grounders (31.1 percent to 26.1 percent), and that's going almost directly to an increase in line drives (17 percent to 21.8 percent). Keeping balls off the ground is generally going to get you better results. It has been for Raleigh, as he's also seen his HR/FB rate increase from 17.4 percent to 24.2 percent.
All that's adding up to a .391 wOBA that's paired up with a .392 xwOBA. That tells us that the results he's gotten this season have been true. Without much change in his batted ball profile, there's not much reason to think things may sway all that far from where they're at now.
Cal Raleigh dumps his 14th HR of the season into the left field seats #RivalryWeekend pic.twitter.com/UUf1j0LBgX
— MLB (@MLB) May 17, 2025
Pitchers have been mainly attacking Raleigh with a four-seam, changeup, and slider approach. Both the four-seam and changeup have positive regression coming for Raleigh. His .315 wOBA against four-seamers has a .346 xwOBA while his .240 wOBA against changeups has a .302 xwOBA. Neither of those is incredibly impressive, but they certainly are very doable numbers for the top two pitches he faces.
With sliders, the 28-year-old starts to see much more positive results. He hits them for a .479 wOBA paired with a .410 xwOBA. Negative regression is there, yes, but an xwOBA above .400 is one hell of a floor to have. The next two pitches he faces most are ones he crushes as well. He sees cutters 9.9 percent of the time (.505 wOBA, .495 xwOBA) and sees sinkers 9.2 percent of the time (.585 wOBA, .535 xwOBA). I'll never know why pitchers even try with these two against him.
Verdict: Big Dumper is in great form, and what we see from him doesn't appear to benefit from much luck. If he's not on your roster and you're in need of catching help, then do what you can to get him. If someone sends you a trade offer and wants to snag Raleigh from you, then question their intentions and don't give in.
Geraldo Perdomo, Arizona Diamondbacks
2025 Stats: .899 OPS, 149 OPS+, 6 HR, 37 RBI, 25 R, 11 SB
Do you like switch hitters? Because I've got another one for you. Perdomo has started off hot for Arizona, giving them a boost at the bottom of their lineup that helps guys like Corbin Carroll and Ketel Marte get more RBI opportunities when he's able to get on in the seven or nine spot (where he traditionally hits). After a couple of fairly average seasons, it looks on the outset that Perdomo has figured some things out.
Perdomo gives you two pretty different looks depending on which side of the plate he's hitting from. As a lefty facing righties, he hits for a .265/.396/.478 slash line, adding up to a .874 OPS. As a righty facing lefties, he slashes .396/.426/.528, adding up to a .955 OPS. You would assume with the higher OPS that he's much more likely to hit for power when facing lefties, but that's not the case.
He's hit five HR against righties but only one against lefties. Quite simply, if you're looking for power numbers, he's got to hit as a lefty. When he's a righty, then you're expecting much more contact than power. If your league is scored based on categories, then this would be something to remember.
Geraldo Perdomo had 3 Home Runs last season.
In the 17th game this Perdomo has hit his 3rd Home Run of the season.
Perdomo is also hitting .327 BA, & a .922 OPS. You love to see it.
— 🌵 Mr. Az (@MrAzSports) April 15, 2025
A big reason for Perdomo's success so far is his ability to draw walks. He's walking at a 15 percent rate, a career high if you exclude his 11-game stint in 2021. His strikeout percentage is also down to 10.6 percent, a career low. He's making pitchers work, and when it's getting in play, it's finding holes.
From a batted ball profile perspective, much of what he's doing is the same in 2024. There's a three percent swing in grounders and line drives (he's hitting fewer grounders and more line drives), and the fly ball rate is about the same. His HR/FB rate is up to 10.3 percent. That's not terribly impressive, but it is a big jump as he holds a career mark of 4.8 percent.
So far, everything has been peaches and cream for Perdomo, but we haven't started looking for signs of either positive or negative regression. He has a .389 wOBA, but that's paired with a .346 xwOBA. That's a healthy chunk of negative regression that will hit soon, but still puts him in the 65th percentile. It's strong, but not current levels strong.
He's done most of his damage this season against four-seam fastballs, hitting them for a .404 wOBA and a .391 xwOBA. A little luck, but nothing crazy. He sees them 43.7 percent of the time, so a majority of who he is will come from his success against this pitch. It's what's happening against sliders and sinkers that paints a clearer picture, though.
Geraldo Perdomo @Dbacks se fue de 2-1 con 1 cuadrangular, el sexto de la temporada, 1 anotada, 3 remolcadas (37), 1 base por bolas y 1 elevado de sacrificio. Batea .302 #AguiluchosMLB pic.twitter.com/sxyFQlBUaX
— Águilas Cibaeñas (@aguilascibaenas) May 20, 2025
Against sliders, which he sees 12.4 percent of the time, Perdomo hits for a .391 wOBA and a .340 xwOBA. That's a decent chunk of negative regression coming for the pitch he sees second most. Against sinkers, he's hitting them for a .382 wOBA and a .252 xwOBA. This is a backbreaker given his current success against the pitch, which he sees as the third-most.
The only pitch that Perdomo is seeing positive regression on is curves. He's hitting them for a .390 wOBA and a .444 xwOBA. If he can continue crushing curveballs then he'll stave off some future slumps, but every other pitch after curveballs are ones he's expecting negative regression from.
Verdict: The gap between wOBA and xwOBA is too hard for me to ignore. Without much change in his batted ball profile, it looks like Perdomo has been benefiting from a bit of luck this season. While he's improved, he's overachieving at this point. When negative regression hits, we should expect him to land somewhere in the 115-120 range for OPS+. Solid, but not elite.
Spencer Torkelson, Detroit Tigers
2025 Stats: .865 OPS, 144 OPS+, 12 HR, 38 RBI, 32 R, 1 SB
No more switch hitters. Well, at least for this article. Torkelson hits from the right side of the plate and finally looks to be the hitter he was expected to be as the No. 1 overall pick of the 2020 draft. A demotion to the minor leagues last season helped catapult him to the hitter he is this season, and the AL-leading Detroit Tigers are more than thankful for it.
Torkelson's plate approach mirrors similar trends we've seen from both Perdomo and Raleigh. Strikeouts are down (27.6 percent to 23.6 percent), and walks are up (8.7 percent to 12.3 percent). Drawing more walks is one of the best ways to keep yourself in lineups, and the 25-year-old is doing a fantastic job with his eyes at the plate.
Spencer Torkelson on May 2nd:
2024:
.219/.291/.298
.590 OPS
0 HR / 11 RBI2025:
.239/.353/.502
.902 OPS
9 HR / 26 RBII’ll never get tired of seeing this transformation.pic.twitter.com/BlHzBGlOyD
— Benson (Miguel Cabrera’s Bat) (@Miggysbat) May 2, 2025
His batted ball profile shows he's making a concerted effort to get more balls in the air and punish them when he does. His groundball rate has decreased (34 percent to 29.4 percent), while his flyballs are up (50.8 percent to 53.2 percent), and his line drives are up as well (15.1 percent to 17.5 percent). That's leading to an increase in the HR/FB rate, which is up to 17.9 percent on the season.
Everything seems to be on the up and up for Torkelson. The good news is that it should get a little better for him soon, too. His .369 wOBA is paired with a .386 xwOBA, meaning we've got two golden words coming for him: positive regression.
Part of that positive regression can be seen by looking at his .254 BABIP. Generally, you will see that number sit around .300 or so, but Torkelson's career mark is .267. So, a big bump in more balls in play turning into hits may not happen, but we should expect that number to get closer to .275 at some point soon.
Spencer Torkelson, who cranks dingers and drives in runs 😤 pic.twitter.com/5Axvmpj1jn
— MLB (@MLB) May 17, 2025
We also should expect positive regression for him on three pitches in particular: Four-seamers, sinkers, and cutters. He's done the most damage against four-seamers, hitting them for a .437 wOBA and a .473 xwOBA. He's hitting sinkers for a .376 wOBA and a .442 xwOBA, one of his biggest jumps in terms of expected positive regression.
Cutters could be a make-or-break type of pitch for him, though. He only sees them 8.9 percent of the time and is hitting them for just a .270 wOBA. But that's paired with a .375 xwOBA and shows huge potential if pitchers start to throw him more of them. If they feel that it will be a successful pitch because he hasn't hit them well, then they'll be in for a bit of a surprise once that positive regression hits.
Verdict: Torkelson is doing all the right things so far this season, and fantasy owners should expect even more good things to happen for him in the near future. They shouldn't let him go and need to have him in their lineups, as an already productive hitter is likely to become even more productive soon.
Kyle Stowers, Miami Marlins
2025 Stats: .947 OPS, 154 OPS+, 10 HR, 30 RBI, 23 R, 2 SB
Maybe the season Stowers is having is flying a bit under the radar due to the fact that he's a Marlin, but the 27-year-old is really tearing it up. He leads the Marlins in homers, runs, RBI, OPS+, you name it. He's essentially been their offensive MVP. The Marlins are happy to see that as he was underwhelming last season after being traded from Baltimore. But in 2025 he seems to have turned over a new leaf.
Stowers, like our other highlighted players, has seen positive improvements with his plate approach. Strikeouts are down (35.4 percent to 28.7 percent), and walks are up (6.2 percent to 9.4 percent). The 28.7 percent mark is still a bit higher than you'd like to see, and he whiffs at an incredibly high rate, too, but when he's getting it in play, he's making pitchers pay.
A huge reason for Stowers' turnaround this season is a drastic reduction in grounders. He was hitting them at a 49.6 percent mark in 2024, and that's dropped to 38 percent this season. Fly balls (32.8 percent to 38 percent) and line drives (17.6 percent to 24.1 percent) are both up, leading to a ridiculous 24.4 percent HR/FB rate. Hitting fly balls at a 38 percent rate isn't incredibly high, but he's making his mark when he does get them in the air.
The league leader in Barrel% over the last month isn’t a name that would be your first guess.
It’s not:
Shohei Ohtani
Aaron Judge
Oneil CruzIt’s Kyle Stowers at 27.4% over the last 30 days. He’s been swinging on the hottest bats in the sport!pic.twitter.com/cLV2yfQ7AI
— Running From The OPS (@OPS_BASEBALL) May 20, 2025
It's all leading to a crazy .405 wOBA and a .406 xwOBA. That xwOBA ranks in the 93rd percentile and puts him just a touch behind guys like Manny Machado and Corbin Carroll. According to Yahoo, he's only owned in 69 percent of leagues while Machado and Carroll are both understandably owned in all leagues. Without a huge gap in wOBA and xwOBA, it seems like Stowers would be the perfect addition to anyone's roster.
Pitchers are throwing Stowers four-seamers 42 percent of the time. A smart man would wonder why when they see that he hits them for a .418 wOBA and a .486 xwOBA. A smarter man would suggest throwing him more changeups, which sounds iffy at first when you hear he's been hitting them for a .395 wOBA, but much more relieving when you see his .286 xwOBA paired up against that.
It's quite the swing on the two pitches, but you'd expect positive overall regression from the two, given just how often he sees four-seamers. The pitch he sees the third most, and what I'd expect pitchers to start throwing him more, is the slider. He's hitting it for just a .272 wOBA that is buoyed by a .271 xwOBA. It's the most accurate result he gets against any pitch, and as he ascends higher in the rankings, you'd think pitchers attack him here more often.
2nd HR of the night
10th of the season
Kyle Stowers keeps on raking! pic.twitter.com/zgYQ2alaXE— MLB (@MLB) May 15, 2025
The one area that we can really expect negative regression to hit is shown in his BABIP. As we mentioned earlier, you typically will see a .300 number regardless of how good a hitter is. Stowers currently has a .398 BABIP, way higher than we'd anticipate. Part of this is likely because of how many line drives he's hitting, but at some point, those will fall off. Last season, he saw his BABIP sit at .319, which I think is a fair mark to expect for him going forward.
Verdict: The lefty is overachieving, but the results he's gotten when he's hit have spoken for themselves. He will struggle with strikeouts but will make you pay with his power. You shouldn't expect him to keep tearing it up every single week but if and when negative regression hits he will still be hitting it hard. There's currently no reason for him to not be on any roster and if he's available in your league you should snatch him up immediately.
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