Fantasy Baseball Breakouts or Fake Outs? Hitters Delivering Elite Results - Part 13

August 15, 2025

Kevin analyzes four hitter fantasy baseball sleepers who are surging for Week 20. Are they breakouts or fake outs? Read his fantasy baseball outlooks and buys/sells.

We're onto the 13th edition of our Fantasy Hitter Breakouts or Fake Outs analysis. How much luck have the expected stats given you? Or is the number 13 less of a sign of luck and more of a sign of the gloominess and darkness that negative regression brings with it? Only time (and xwOBA, I guess) will tell.

Heading into Week 20, there's a bit of digging we need to do to help you find those diamonds in the rough that can help you win your fantasy championship. Buying into current hype can be easy, but understanding luck can set you apart from the rest of your league.

We'll break down four hitters for you this week. August is a critical month in the MLB schedule. It's a make-or-break time not just for teams vying for playoff spots but also for fantasy managers aiming for playoff spots as well. Today, we'll break down Kerry Carpenter, Andrew Vaughn, Yainer Diaz, and Luke Keaschall. Now, let's get into it.

All statistics in this article reflect games played through Sunday, August 10th.

Kerry Carpenter, OF, Detroit Tigers

2025 Stats: .843 OPS, 127 OPS+, 21 HR, 45 RBI, 48 R, 1 SB

After dealing with a hamstring injury that held him out most of July, Carpenter has come back with a vengeance. It's only been 12 games, but his 1.313 OPS and five homers in that time have certainly helped the Tigers get back into the swing of things after their mini-funk. The lefty is dominating, but you know the deal by now.

Do the numbers say it's real? Or do we have a fake-out on our hands? Let's dive in.

Kerry Carpenter has established a new career high with 21 homers this year.

His .598 SLG vs. right-handers since the start of 2024 ranks 3rd in baseball (min. 500 PA vs. RHP), behind only Shohei Ohtani and Aaron Judge. pic.twitter.com/xeRWIujz2B

— Tigers PR (@DetroitTigersPR) August 11, 2025

Carpenter's plate approach has one very worrying characteristic right off the bat. His walk rate is sitting at just 2.5%, a very minuscule number in today's game. After posting numbers of 7.4% and 7.0% in the past two seasons, this isn't something we like to see. It's fine for now, but we want that rate higher in the future.

His strikeout rate has dipped to 22.3%, the lowest in his four-year career by 3.0%. That's just a touch worse than league-average, but it's a fine mark since he generally gets good contact on his pitches. More balls in play are typically going to be a good thing for the 27-year-old; we don't want to see it come at the detriment of walks.

Ironically, Carpenter's strikeout rate has risen to 28.9% during this hot streak while his walk rate is still very low at 2.6%. He's taking a lot more chances this time around by going for the big swing more often. In this mini hot streak, it's paying off, but if he can limit the strikeouts while keeping the same quality of contact, then that will be our sweet spot.

His batted-ball profile shows a few good improvements as well. The most crucial factor is that his ground-ball rate is down to a career low of 31.9%. It sat at 37.5% last season after being at 44.7% in 2023. We're seeing an increased focus on getting the ball in the air one way or another.

In this 12-game sample, since he's returned, that ground-ball rate is at a miniscule 19.2%. Nearly everything he's hitting is getting in the air. If the strikeout rate is going to rise, he's at least doing all he can to make sure the balls in play he does get are productive. Sustainable? Likely not, but once again, we're seeing that concentrated effort to get the ball in the air.

From a season-long perspective, we're seeing both his fly-ball rate and line-drive rate increase. That makes natural sense given the decrease in grounders. The fly-ball rate is up to 49.1% from 44.8% last year, and the line-drive rate is up to 19.0% from 17.7%.

His HR/FB rate is right at his career norms, coming in at 18.4%. It's a decrease from last season's 20.9%, but the continuation of the trend suggests we're getting what we usually get from Carpenter when he gets it in the air.

Now onto the expected stats. Carpenter's wOBA comes in at .356 on the season, the second-best of his career. But his xwOBA is listed at .346, lower than the .379 mark he posted last season. Now, maybe 2024 is unfair to compare against since he posted a 157 OPS+ that season, but, surprisingly, his xwOBA is that low given what we're seeing in his batted-ball profile.

So let's check off the rest of the list. His BABIP is coming in at .284, pointing towards a touch of potential positive regression unless he's not hitting the ball as hard as he usually does. But he's actually posting a career high in hard hit rate at 47.0%. His 14.2% barrel rate puts him in the 87th percentile, and his xSLG is in the 92nd percentile.

Those signs all tell me that there has to be something else funky going on. Perhaps it's the 2.5% walk rate that xwOBA dislikes, which predicts negative regression, even though it's not particularly detrimental. Count me as someone who's not fully buying into that drop from a full-season perspective.

Let's look at the pitch mix and see if anything sticks out, though. Immediately in the first two pitches, we can see that one is expecting a touch of positive regression, while the other is predicting a lot of negative regression. The good news is four-seamers are what he's expecting positive regression on, as he sees those the most of any pitch.

THREE HOME RUNS FOR KERRY CARPENTER

HAVE A NIGHT! pic.twitter.com/BUyZ1RV7Of

— MLB (@MLB) June 3, 2025

On four-seamers, he's hitting them for a .339 wOBA to go with a .367 xwOBA. Not overwhelmingly elite, but any time we're expecting positive regression on the pitch, we see the most, that's a good thing.

It's changeups that have me a little worried, though. He hits those for a .355 wOBA, but that's paired with a .261 xwOBA. That near 100-point drop is going to hurt. And since changeups play well off of four-seamers, that's going to come soon.

If only there were a pitch he already rips and still expects positive regression on. Oh, hey, sinkers! Good to see you!

When looking at the numbers, I don't understand why any pitchers would want to throw sinkers to Carpenter. He hits them for a .579 wOBA to go along with a .556 xwOBA. That's absolutely nuts. Of all hitters who have seen 100 sinkers or more, only three batters have better expected stats: Brett Baty (.617 xwOBA), Cal Raleigh (.597 xwOBA), and Aaron Judge (.575 xwOBA). Not bad company to keep!

The other pitch he sees that looks to be a potential difference maker is cutters. He sees them 10.4% of the time and is hitting them for a .420 wOBA. Unfortunately, that's paired with a .331 xwOBA. With him seeing these almost as often as sinkers, it negates some of the really good things we see from that pitch.

The last thing to mention with Carpenter is that he's mainly a platoon hitter. While he's excellent against righties, you're not going to see him hit often against lefties. This puts him at risk of being pulled from games early, so fantasy managers need to be aware of that when plugging him into their lineups.

Verdict: You don't need me to tell you that Carpenter is overachieving since returning from injury. But I don't fully buy into the negative regression dip that xwOBA is predicting from a full-season perspective. Yes, we have some worries in the pitch mix. But overall, he's doing good things when he gets the ball in play in terms of getting it into the air.

When all is said and done, I don't believe he'll get close to a 150 OPS+ like he did last season, but it's more than reasonable to expect him to stay around 125-130. That's very good, especially since he's only owned in 63% of Yahoo! leagues at the moment. Snag him up if you can and ride the hot streak until he gets back to his normal self.

Andrew Vaughn, 1B, Milwaukee Brewers

2025 Stats: .701 OPS, 94 OPS+, 12 HR, 47 RBI, 24 R, 0 SB

Find me a person in Milwaukee who doesn't love Andrew Vaughn already. That's a Mission Impossible I'd actually watch. Sorry, Tom Cruise, but you're no match for King Vaughn.

He's earned it by posting a 1.041 OPS for Milwaukee in 102 PA, translating to a 190 OPS+. Much better than his time with Chicago. But is he for real? Or do we have a fake-out on our hands? Let's find out.

ANDREW VAUGHN IS THE GREATEST PLAYER IN BREWERS HISTORY pic.twitter.com/C487cQ1JZg

— The Brew Crew Scoop (@BrewCrewScoop) July 30, 2025

From a full-season perspective, Vaughn has posted a 19.0% strikeout rate to go along with a 5.8% walk rate. Both are close to in line with what he posted in Chicago last season. His rates with Milwaukee are much improved, though. As a Brewer, he has a 12.7% strikeout rate and a 9.8% walk rate.

The strikeout rate may regress, as it's much lower than his norms, but there may be some hope that the 9.8% walk rate may not fall that far. That's because in his rookie season, he posted an 8.7% walk rate. He has generally been at or right below a 6.0% walk rate for most of his career, so this would be a career high for him. But there may be hope his eye is that good right now.

Now let's move on to his batted-ball profile. From a full-season perspective, we see one concerning trend as he's hitting more groundballs. His ground-ball rate has risen to 43.9%. That's taking away from his fly-ball rate, which has dropped to 38.0% from last season's 45.8% mark.

That drop may not be all that concerning, though, as Vaughn has traditionally had a fly-ball rate around 38%. So this just kind of fits the bill for who he is. His line drive rate is also in line with his career norms, coming in at 18.1%.

His batted-ball profile as a Brewer, though, raises a couple of questions. For Milwaukee, his ground-ball rate has risen to 48.7%, a higher rate than his full-season mark. His next highest ground-ball rate was 47.7% in 2022, though he hit for a 111 OPS+ that season, so he can still find ways to succeed with a rate that high.

What has Brewers fans liking Vaughn, though, his his HR/FB rate. That's currently sitting at 29.2% with him as a Brewer, making it feel like any time he gets it in the air, that it's going out. His seven homers for Milwaukee have already passed his mark with the White Sox, helping to prove that he's just seeing the ball a lot better right now, like his walk rate and strikeout rate are showing.

Now for the expected stats. I'm guessing that Brewers fans are going to like this part. On the season, he's posted a .302 wOBA, but that's paired with a .350 xwOBA. That xwOBA ranks in the 71st percentile and is a massive jump for the 27-year-old. Positive regression that big doesn't just come around.

That's backed up by a few things we love to see. The first is his .258 BABIP. That should jump up closer to .300, as we expect. He currently has a .338 BABIP with Milwaukee. That obviously will drop, but at .258 on the season, we can view that as positive regression being realized.

Further backing up the positive regression, Vaughn has a 50.2% hard-hit rate (88th percentile) and a 13.1% barrel rate (82nd percentile). Between these marks, his sub-.300 BABIP and a rising xwOBA in his last 100 PAs (see below) all point to more positive regression coming for him.

Now for the pitch mix he faces. It becomes very clear with one pitch why he's expecting so much positive regression. Let's start with four-seamers and sliders. He sees four-seamers 30.1% of the time, hitting them for a .377 wOBA and a .389 xwOBA. He sees sliders 18.7% of the time and hits them for a .404 wOBA, also with a .389 xwOBA.

While four-seamers have positive regression and sliders have negative regression, they're going to balance each other out. Besides, a .389 xwOBA is a really nice floor for both pitches to have.

After his home run in the 5th inning, Andrew Vaughn is now hitting .349 with 4 HR and 15 RBI in 14 games for the Brewers. pic.twitter.com/7JjwTkUPt1

— Hunter Baumgardt (@hunterbonair) July 29, 2025

Now for the big one. Sinkers have been the bane of his existence so far, seeing them 14.5% of the time and hitting them for just a .198 wOBA. It's the worst wOBA he's posted against any pitch this season. However, he's got a .346 xwOBA against that pitch. That's a ton of positive regression that he's going to realize soon.

Will he get all of that as a Brewer with just two months left in the season? Probably not, but that's a significant gap to ignore, especially with positive regression.

The pitch he's going to struggle with, and pitchers need to try to use more against him, is the sweeper. He's only hitting them for a .226 wOBA to go along with a .230 xwOBA. Those results are somewhat true, and pitchers who have good sweepers will likely try to focus on using those against the 27-year-old a lot more.

Verdict: Vaughn is benefiting from two key factors: a new environment and positive regression. All signs are pointing upwards for King Vaughn as Milwaukee continues its strong march towards October.

At 53% owned in Yahoo! leagues, there's a good likelihood that he's available on your waiver wire. Go snatch him up and get him in your lineup immediately. With that much positive regression, and his top three pitches all having an xwOBA of .340 or better, he's got a real solid floor that will help you out to end this season.

Yainer Diaz, C/1B, Houston Astros

2025 Stats: .697 OPS, 90 OPS+, 16 HR, 50 RBI, 42 R, 1 SB

Diaz appeared to be the answer for Houston at catcher over the past couple of seasons. With a 128 OPS+ in 2023 and a 116 OPS+ in 2024, it seemed like his bat would be a massive contributor in Houston's lineup.

But 2025 hasn't quite been the same. He's down to a 90 OPS+ this season. July was his best month this season as he hit for an .842 OPS with five homers and 10 RBI. Was what we saw in July what we can expect from Diaz going forward? Or was that breakout a bit more of a fake-out? Let's dig in.

YAINER DIAZ. GRAND SLAM. pic.twitter.com/ZtwN9BxESa

— Houston Astros (@astros) April 12, 2025

First, we'll look at his plate approach, as always. We see minimal changes here, with his strikeout rate (16.7%) and walk rate (3.6%) being very close to his marks last season. As we pointed out with Carpenter earlier, the walk rate is much too low and needs to improve to help him find more ways on base.

Part of that low walk rate, though, is that it's just who Diaz is right now. He hasn't posted a walk rate of about 3.9% in a year where he's gotten extended playing time. It's an approach that works for him, but the number is too low for me to consider it a good thing for him.

Now for his batted-ball profile. There are improvements from last season between groundballs and flyballs, with his profile looking very reminiscent of his 2023 season. His ground-ball rate is at 45.0% (51.2% last season), fly-ball rate is at 36.0% (26.3% last season), and his line-drive rate is at 19.0% (22.4% last season).

In 2023, when he posted a 128 OPS+, he had a 43.2% ground-ball rate, 36.6% fly-ball rate, and a 20.2% line drive rate. So what's the significant difference between then and now? Well, his HR/FB rate in 2023 was at 21.9% while this season it's at 13.4%.

That difference is an important reason why he's only at a 90 OPS+ this season. The 2023 season is a great comparison too, as he's played in the same number of games but has more PA. He hit 23 HRs in 2023 but has only 16 this season. The good news is he'll pass last season's mark (16 HR), but he's still not seeing the same results outside of homers.

Now for the expected stats. He's hitting for a .299 wOBA on the season, but that is paired with a .337 xwOBA. His 43.8% hard-hit rate (54th percentile) and 8.8% barrel rate (49th percentile) at least tell us he should be closer to a league-average wOBA, so positive regression is justified here.

Considering his .267 BABIP, it only reinforces the notion that positive regression is likely to follow. One other thing I find interesting is that his xwOBACON this year (.392) is only a touch behind his mark last season (.395). With his strikeout rate and walk rate remaining so similar from season to season, we should probably see him hit closer to the .329 mark he hit last season.

Yainer Diaz has been hot for a month now pic.twitter.com/G4TvLV56PU

— Ari Alexander (@AriA1exander) August 6, 2025

So, positive regression appears to be justified. Now for the pitch mix, and it's more good news for Diaz. Each of the top three pitches he sees is expected to show positive regression, and they make up just over 60% of all pitches that he sees.

He's hitting four-seamers for a .365 wOBA to go along with a .386 xwOBA. He's hitting sliders for a .253 wOBA, a low mark, but that's paired with a .339 xwOBA. Sinkers, a pitch he's been outstanding against, are being hit for a .383 wOBA to go along with a .401 xwOBA. Sliders will provide a big jump, while four-seamers and sinkers each have an excellent floor.

One pitch he's struggling against now, and will continue to struggle against, is sweepers. He's only hitting them for a .215 wOBA, and that's paired with a .198 xwOBA. As long as pitchers can throw a decent one, they're likely to focus on this against the 26-year-old.

Verdict: Diaz looks like a clear case for positive regression. He's putting the same amount of balls in play as he did last season, with a batted-ball profile similar to 2023, but the numbers haven't shown it. BABIP and xwOBACON all point towards positive regression, and most of it will come on the top three pitches he sees.

At 83% rostered in Yahoo! leagues, he's likely not on your waiver wire, but if he's on your roster, then it may be time to start plugging him in. That positive regression will feel nice when it hits, especially with the fantasy playoffs coming up here shortly.

Luke Keaschall, 1B/2B/OF, Minnesota Twins

2025 Stats: 1.207 OPS, 226 OPS+, 2 HR, 12 RBI, 6 R, 5 SB

At this point in the system, you're looking for hidden gems, and that always puts late-season callups in the spotlight. Where better to find magic than with someone that you know the rest of your league hasn't heard of?

Luke Keaschall falls into that category. The Twins' No. 3 prospect made his major league debut earlier this season but had been out since late April due to a forearm fracture. He made his return a week ago and has been lighting it up. He has a hit in 11 of 12 games (before Monday night's action), and five of those have been multi-hit games.

His 1.207 OPS is appealing to anyone and everyone, and we know he's probably overachieving, but will he be a solid option when he levels off? Let's dig in and find out.

Luke Keaschall #WALKOFF homer!

The @Twins win it in the 11th! pic.twitter.com/zEmFEWVk7C

— MLB (@MLB) August 10, 2025

First, we'll take a look at his plate approach. Both his walk rate and his strikeout rate look fantastic, but one's more real than the other. His strikeout rate currently sits at 6.3%. He's generally been around 17%-19% in the minors, so we should expect his strikeout rate to increase the more he plays.

His walk rate, though, might be more real. His walk rate is 10.4%, which is actually below the marks that he's been posting in the minors. Generally, he's been around 13%-14% over the past two seasons in the minors, telling us that rate could potentially be even higher. But with this being his first foray in the pros, 10.4% is more than acceptable.

Now for his batted-ball profile. His ground-ball rate and fly-ball rate are both identical at 39.5%. Interestingly enough, his rates in Triple-A St. Paul were similar to each other, both being at 36.3% this season. His line-drive rate sits at 21.1% in his short time with the Twins. It's been a higher mark throughout his minor league career, typically being closer to the mid-20s.

With two homers in the majors, Keaschall's HR/FB rate sits at 13.3%. That's hard to trust given the very small sample size, but the good news is it's in line with what he traditionally has posted in the minors. In Triple-A this season, he had posted a miniscule 3.4% HR/FB rate, but that's an anomaly as he's normally been around 11%-12%.

Now to the expected stats. Small sample sizes obviously lead to more skewed stats, so we need to take some of these results with a grain of salt. But Keaschall's currently got a .510 wOBA to go along with a .400 xwOBA. Needless to say, that's very good!

To dig further into what's real at this level and what isn't, we need to see what his hard-hit rate is. It's currently sitting at 36.8%, which would put him near the 23rd percentile in the majors if he were qualified. Not great, but his barrel rate of 10.5% would rank closer to the 64th percentile, so it's not all bad.

With such early success, it also shouldn't be surprising that his .417 BABIP is well above the normal .300 mark we look for. In the minors, he'd generally posted a mark above .300, usually coming in around .330 or so. A higher BABIP won't be surprising for Keaschall to post, but obviously, a .417 BABIP will be unsustainable going forward.

where were you when luke keaschall saved the twins pic.twitter.com/mwIN8HXntn

— Kaleb (@PrimeERod) August 5, 2025

Usually, I'd break down the pitch mix here in this section, but I think it's too hard to gain anything real given such small sample sizes. He does have an xwOBA of .400 or better against all pitches he's put in play besides sliders. But there's not a whole ton to gain here until we start to see how the league adjusts to him, which likely won't be for another couple of weeks.

What I think is essential to dive into further is Keaschall's stats in the minor leagues. In 2024, he posted a .416 wOBA throughout both Double-A and Low-A. In 2023, he posted a .416 wOBA as well through Single-A. In Triple-A this season, he posted a .334 wOBA in 118 PA.

I take the Triple-A numbers with a bit more of a grain of salt, especially since his stint in July was him getting back into the swing of things after injuring his forearm. It's clear that he has a ton of potential, and I like his ability to draw walks, a skill that will significantly help him moving forward.

Verdict: Keaschall is an obvious buy candidate. Is he going to keep doing what he's doing? Probably not. Though he's been around a .400 wOBA in the minors, we need to expect that number to be lower. I would believe he'll probably end the season closer to a .350 wOBA, but that's very acceptable for a rookie like him.

At 50% rostered in Yahoo! leagues, it's clear the word is out. If you haven't looked for him, then do so immediately. You'll be thankful you did if he's sitting there ripe for the picking.

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