Fantasy Baseball Breakouts or Fake Outs? Hitters Delivering Elite Results - Part 15

August 28, 2025

Kevin Larson analyzes three hitter fantasy baseball sleepers who are surging for Week 22. Are they breakouts or fake outs? Read his fantasy baseball outlooks and buys/sells.

We're very close to the fantasy baseball playoffs. With those right around the corner, you need to know whether you can buy into surging hitters before making a potentially costly mistake. That's where we come in. We help you evaluate the expected stats, which are tremendously helpful in identifying luck.

This week, we've got three hitters to analyze for you. All three are likely rostered in 50%-60% of standard leagues, but if your league is slacking, then there could be an opportunity with them, making them attractive additions for the fantasy playoffs. That is as long as xwOBA is kind to them.

With that said, let's get ready to dive in. We'll evaluate Mark Vientos, Noelvi Marte, and Bryson Stott. Now let's get to it.

All statistics in this article reflect games played through Sunday, August 24th.

Mark Vientos, 3B/1B/DH - New York Mets

2025 Stats: .695 OPS, 97 OPS+, 12 HR, 43 RBI, 31 R, 0 SB

Vientos missed much of June thanks to a hamstring injury. Prior to that, and well into July, the 25-year-old was hitting for an OPS that was hovering below .690 or so. That seems to be a disappointment after last season's .837 OPS in a breakout season.

But he's turned it around in August, or at least it would seem that way so far. He's posting an .887 OPS this month, much closer to the Vientos we saw last season. So is he finally breaking out? Or do we potentially have a fake-out on our hands? Let's find out.

Mark Vientos has homered in each of his last THREE at-bats! 😤 pic.twitter.com/U8tSJO2Pk8

— MLB (@MLB) August 24, 2025

As we look at his plate approach, we can see that Vientos is working to put more balls in play this season. His strikeout rate is down from 29.7% last year to 22.9% this year. That's a solid improvement. But it's coinciding with his walk rate dropping from 7.3% to 5.7%. Not terrible, but we always want to see that rate increase.

Moving to his batted-ball profile, it becomes a bit odd to see his stats where they're at. That's because we're seeing positive trends with nearly every aspect of his batted-ball profile. His ground-ball rate is down (44.2% to 39.7%), his fly-ball rate is up (36.0% to 38.1%), and his line-drive rate is up as well (19.8% to 22.3%).

All of those should mean good things! So why aren't we seeing the same results? Much of that can be attributed to a stark drop in his HR/FB percentage. Last year it was at 26.5% while this season it's down to 12.8%.

Naturally, that would lead you to believe two things: A drop in hard-hit rate and a drop in barrel rate. Surprisingly, we're not seeing a drop in hard-hit rate. That's actually up on the season to 50.6% from last season's 46.6%. But his barrel rate is down, sitting at 10.5% after last season's 14.1% number.

So that would explain why we're not seeing the same impressive results we saw last season. But with the improvements in the other aspects of his batted-ball profile, we should be seeing better results outside of home runs, right?

That's an answer that hopefully xwOBA can tell us. And it does point towards positive regression, like we were expecting. His .299 wOBA is balanced with a .319 xwOBA. That 20 points of positive regression isn't gigantic by any means, but with four weeks left in the season, it's a decent bump we can hope for Vientos to realize.

One other stat that backs up positive regression is his .277 BABIP. With his hard-hit rate increasing, we should certainly expect something closer to .300 or so. Now in his first two seasons he did post a sub-.300 BABIP, making last season's .324 number potentially an outlier. But I'm comfortable in saying that .300 should be a realistic number to achieve.

Mark Vientos has been on an absolute HEATER this past week:

.375 AVG | 5 R | 9 RBI | 4 HR | .958 SLG | 263 wRC+

Playoff Mark might be making a resurgence 👀🔥 pic.twitter.com/eiRf9eYsTO

— Fireside Mets (@firesidemets) August 25, 2025

Moving onto the pitch mix. As with most hitters, the 27-year-old faces four-seamers the most. And it's probably a big reason that the positive regression he's expecting isn't larger. He currently hits them for a .352 wOBA that's paired with a .320 xWOBA.

In fact, four-seamers may be the most significant reason his stats aren't the same this season. Last year's numbers had a .461 wOBA to go along with a .443 xwOBA. With Vientos facing four-seamers 25.4% of the time this year, the year-over-year drop in overall production is a significant factor holding him back this year.

The next three pitches he sees the most, though, are all expecting positive regression. That comprises sliders (.290 wOBA, .348 xwOBA), sinkers (.294 wOBA, .328 xwOBA), and sweepers (.175 wOBA, .262 xwOBA). They make up 48.9% of all pitches he faces. While none of the xwOBA floors are spectacular, they do show a lot of room for improvement.

The only pitch that Vientos is expecting significant negative regression on is curveballs. He's currently hitting them for a blistering .517 wOBA, but it's paired with a .337 xwOBA. Not the worst floor, but that drop is going to hurt whenever he faces a pitcher with a solid curveball.

Verdict: Count me as someone who's buying into Vientos' August as more of the real Vientos than what we've seen for most of this season. He's putting more balls in play and is hitting them harder than last season. The barrel rate dropping is a concern, but it's still above league average. He should be seeing better results than he's getting.

Buy into Vientos down the stretch. The 20 points of positive regression he should be expecting may not be fully realized by season's end, but there's no reason to expect his OPS+ to stay below 100 like it is. Expect it to rise to around 105 when all is said and done, and ride his hot streak to the finish line.

Noelvi Marte, 3B/OF - Cincinnati Reds

2025 Stats: .856 OPS, 128 OPS+, 10 HR, 40 RBI, 32 R, 7 SB

Another player that's starting to make waves after being on the injured list, Marte has been a key piece of offensive production for the Reds while they fight for the NL wild card. He's been relatively consistent throughout the season as well, but his August has been spectacular (.329/.346/.566 slash line).

With Cincinnati needing him down the stretch, the stress levels will be high. They'll be hoping for him to produce like he has all season. But is his August a sign of more to come? Or is it a fake-out? Let's dig in.

Noelvi Marte circles them all for the @Reds 😅 pic.twitter.com/WX2DZnkCxw

— MLB (@MLB) August 24, 2025

First, let's look at his plate approach. We see a significant improvement in his strikeout rate as it's dropped from 31.0% in 2024 to 18.8% this season. With about the same number of plate appearances, it's a great sign to see. It also lines up with his strikeout rate in his rookie season, in which he posted a 20.3% rate. This is more of the hitter he's been in the minor leagues.

We're also seeing his walk rate slightly increase from 3.7% to 4.3% this season. That's a very low number that we'd love to see increase. His walk rate in the minors has generally been closer to 10%, so there's an area of opportunity here for the 23-year-old.

As we move on to his batted-ball profile, we can see some slight overall improvements. His ground-ball rate is slightly down (45.2% to 44.1%), his fly-ball rate is up (34.8% to 37.9%), and his line-drive rate is down (20.0% to 18.1%). These aren't all that different overall, so how did we go from a 49 OPS+ last season to a 128 OPS+ this season?

The answer lies in his HR/FB rate. That's doubled from 7.4% last season to 14.9% this season. That also nearly matches his 13.6% mark from 2023, when he posted a 118 OPS+. Maybe last season's marks were pointing to a down season that's out of character for him.

But we still need to dig further, so let's see what the expected stats say. His .366 wOBA is paired with a .338 xwOBA. So it's predicting negative regression, but we need to check a few other boxes first. His .335 BABIP supports the idea of negative regression. His hard-hit rate of 37.3% is below league average as well, further supporting negative regression.

Marte is at least barreling the ball decently, though. His 9.6% barrel rate is in the 55th percentile, giving us confidence that he's at least going to perform at a league-average level there and that not all of his production is aided by luck.

Noelvi Marte’s last two games:

6-for-9
5 XBH
4 runs
5 RBI

.837 OPS on the year 🔥
pic.twitter.com/zUzi7Azthr

— Just Baseball (@JustBB_Media) August 10, 2025

Now let's dig into the pitch mix to see what we can find out. As we're expecting negative regression, it shouldn't be all that shocking to see that the top five pitches he's facing all point towards negative regression as well. These make up 79.5% of his total pitch mix, making it almost certain that negative regression isn't a fluke.

The biggest difference makers will be four-seamers (.424 wOBA, .374 xwOBA), sinkers (.438 wOBA, .371 xwOBA), and curveballs (.470 wOBA, .376 xwOBA). That's a ton of negative regression coming on three pitches he's strong against. But, at the same time, all have an xwOBA of .370 or better. If there's a floor to fall to, might as well be this one.

The only pitch on which Marte expects positive regression is cutters, but he sees them only 5.8% of the time, and the expected positive regression is minimal. This won't be a difference maker.

The good news with Marte's negative regression is that five of the top six pitches he faces all have an xwOBA floor of .350 or better. The only worry is sweepers. He only hits those for a .231 wOBA, and that's paired with a .183 xwOBA. As long as he can avoid pitchers with a good sweeper, he'll be fine.

Verdict: It's hard to deny that the 23-year-old is currently overachieving, especially with so many of the advanced stats pointing towards negative regression. The big question really is just about where Marte will settle after the negative regression.

His current 128 OPS+ should likely fall to 110 or 115. The other worry to consider is that Cincinnati's schedule to finish the season is a bit rough. That's quite a bit lined up against Marte. He's still going to produce at a decent level, but try not to get too used to the results he's currently putting up. He's got a spot in your lineup, don't view him as a savior.

Bryson Stott, 2B/SS - Philadelphia Phillies

2025 Stats: .692 OPS, 89 OPS+, 9 HR, 53 RBI, 55 R, 21 SB

Stott got off to a real hot start this season, posting an .810 OPS in his first 27 games. But that was filled with a bunch of disappointment from May through July. The script has flipped in August, though, and he's back to a blistering .978 OPS in the month.

But that high of an OPS has never been who Stott is. So is this just an instance of Stott realizing a bunch of positive regression with more to come? Or is it a fake out? Let's find out.

These recent Bryson Stott swings are the prodigal Prince that was promised when he first got to Philly

Batting .300 since the All-Star break now

Love seeing this from the 9-hole hitter pic.twitter.com/TkGPircefy

— Aidan Powers (@aidan_34_powers) August 21, 2025

First, let's break down his plate approach. From season to season, Stott's plate approach is nearly identical. His strikeout rate went from 16.3% to 16.9% and his walk rate went from 9.3% to 9.6%. Overall, these are both really strong numbers to have, but don't show us much of a difference from last season when he had an 86 OPS+.

His batted-ball profile shows some promising trends compared to last season. His ground-ball rate is down (43.1% to 40.6%), his fly-ball rate is up (36.9% to 41.2%), and his line-drive rate is down a touch (20.0% to 18.2%). His HR/FB rate is still at a low number, though, dropping from 7.1% to 6.7%.

Home runs have never been Stott's game, though, so we shouldn't be all that concerned by that number. He's been more of a bat-to-ball type hitter, even if it hasn't been ultra-productive for him.

But let's see what the expected stats say. And they say that, from a whole season perspective, the results Stott's getting are real. His .306 wOBA is paired with a .307 xwOBA. His rolling xwOBA has gotten up to .319 as recently as the 23rd, showing he's outperforming his season-long stats. Not surprising given his hot streak, but it shows potential to outperform his norms.

Stott's BABIP currently sits at .283, pointing towards potential positive regression. That would be if he weren't traditionally a .288 BABIP hitter, so maybe the very slight positive regression xwOBA is pointing towards makes sense instead of seeing a bigger jump.

Additionally, the 27-year-old doesn't usually hit the ball hard. His 29.5% hard-hit rate ranks in the eighth percentile, and his 4.6% barrel rate ranks in the 15th percentile. Neither is very impressive and backs up the idea that Stott is more of a contact hitter who needs to find holes.

But onto the pitch mix to see where there may be an opportunity. The biggest pitch that will make a difference against Stott this season is four-seam fastballs. He sees them more than most hitters do, facing them 42.3% of the time. He's currently hitting them for a respectable .365 wOBA, but that's paired with a .334 xwOBA.

New Dad strength unlocked 💪

Bryson Stott and his wife had their second child today, and he homers tonight! pic.twitter.com/cCao16brsB

— MLB (@MLB) July 24, 2025

That, unfortunately, will take away much of the positive regression we're expecting from the next two pitches he sees most often. Sinkers (.258 wOBA, .318 xwOBA) and sliders (.301 wOBA, .334 xwOBA) make up 25.6% of all pitches he sees. They'll be difference makers, but much will be wiped out thanks to the negative regression from four-seamers.

Verdict: There's too much muddiness in Stott's pitch mix for me to determine whether he'll see positive or negative regression. He clearly was underachieving for much of the season, but the person he's been in August isn't the same person he'll be going forward.

Fantasy managers should view Stott's rest-of-season potential as a .692 OPS hitter rather than his .978 OPS in August. Additionally, his splits in left-on-left matchups leave much to be desired and could put him in a platoon role. I'll buy into the fact that he's better than his current 89 OPS+, but I don't think he finishes higher than 95 by season's end.

Ride the 27-year-old's hot streak for now, but don't be surprised when it dies down.

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