Stuff+ Standouts - Identifying Fantasy Baseball Sleepers and Pitcher Breakout Candidates

March 2, 2025

Dan's Stuff+ fantasy baseball sleepers and 2025 starting pitcher breakout candidates who rate highly in Stuff+ metrics despite not having elite surface numbers.

My quest to find the best starting pitching options for fantasy baseball every year is renewed again in 2025! Last year, I began digging into the Stuff+ statistic to locate pitchers with the upside to turn the corner and have a big season. I'm back at it again this year, searching for fantasy baseball sleepers and starting pitcher breakout candidates for 2025.

Last year we had some hits with Grayson Rodriguez and Bryce Miller while others like Bobby Miller struggled. It's certainly not a perfect science, but taking risks on pitchers with the best "stuff" with the hope that they can clean up other aspects of their performance makes sense - especially with younger pitchers who are still developing.

So in this article, I will examine a handful of pitchers who had borderline elite Stuff+ ratings last season to see if any of them are pitchers worth targeting in 2025 fantasy baseball drafts at their current ADP.

The Pitching+ Stat Background

I'd like to start with a quick introduction to the Pitching+ statistic if you are still unfamiliar.

Stuff+ was created by Eno Sarris as a way to try to quantify the potential effectiveness of every pitch thrown. Stuff+ evaluates the physical characteristics of each pitch - the velocity, movement, and spin rates - to identify the filthiest pitches.

Stuff+ has been relatively sticky from season to season. So the idea here is that pitchers are much more likely to improve their control or learn how to pitch situationally from year to year than they are to make big gains in velocity or increase movement on their pitches.

Let's see if we can use this data to identify some potential breakout candidates in 2024.

Stuff+ Standouts for Fantasy Baseball

The median score for Stuff+ is 100 and one standard deviation is about seven points in either direction. So the group that I identified was right around that 80 to 85% percentile and I tried to choose pitchers who were either young or at less obvious draft targets. The minimum cutoff for innings pitched was 90 and relief pitchers were also excluded from our pool of pitchers.

Garrett Crochet led the league with a 113 Stuff+ rating. Other studs in the top ten included Tarik Skubal (111), Corbin Burnes (112), Hunter Greene (112), Paul Skenes (110), Dylan Cease (+110), Zack Wheeler (109) and Gerrit Cole (109). No one needs to tell you to draft those guys, but the 105 to 108 range brings us some interesting names to discuss.

2025 Starting Pitcher Breakout Candidates

Aaron Civale, Milwaukee Brewers

Age: 29
ADP: 232

Civale appears to be a major outlier on the list. He has the highest ERA and WHIP of anyone in the group and is significantly older than the other pitchers discussed here. Civale split time between Tampa and Milwaukee last season finishing with a record of 8-9 across 161 innings.

This certainly doesn't look like the profile of an elite pitcher.

When we dig a little deeper into the Stuff+ ratings on each of his pitches, we can see that he has two pitches that rate incredibly well - his curveball (140) and slider (138). However, he only threw those pitches a combined 30% of the time and he relies on his cutter (102) and sinker (81) as his primary pitches.

Civale is a guy who throws five different pitches and relies on his ability to mix up his pitches and change location to be effective. However, he simply didn't miss many bats last year (8.9% SwStr%) and had a below-average Location+ rating of 95.

Simply stated, Civale lives on thin margins to begin with due to his lack of velocity and wasn't sharp last season. He has good breaking pitches but isn't able to set those pitches up for success often enough with the rest of his arsenal. He might eat innings again, but we aren't expecting major improvements from him and he might be overdrafted at this ADP.

Taj Bradley, Tampa Bay Rays

Age: 23
ADP: 213

Bradley made some significant strides last season in his sophomore campaign. He lowered his ERA from 5.59 to 4.11 and WHIP from 1.29 to 1.22 while maintaining a strong K% of 26.6 percent. At one point during the season, he looked unhittable, but like a lot of young pitchers, he was streaky with some stretches where he struggled as well.

Remember that six week stretch in the middle of last season when Taj Bradley was one of the best pitchers in baseball?

6/8-7/25: 9 GS, 55 IP, 0.82 ERA, 0.89 WHIP, 22.3% K-BB

Bradley could be a Top-25 SP if he can be more consistent.#FantasyBaseball pic.twitter.com/b34D55DU2m

— Eric Cross (@EricCrossMLB) January 30, 2025

Bradley's biggest weakness is locating his pitches. His walk rate was fine again at 8% but his Location+ rating of 93 suggests that he's not hitting his spots with his pitches.

Bradley has plus velocity on his four-seamer at 96 MPH and two plus pitches to complement it - a splitter and a cutter that both average around 90 to 91 MPH. What he's missing here is an effective offspeed pitch, as he only threw his 79 MPH curveball 9 percent of the time for an 8.8 percent SwStr%.

Bradley is just 23 years old and will continue to develop this season. If he can continue to refine his control and develop an effective offspeed pitch, he has the potential to be very, very good. He's a solid value at this stage in the draft.

Ryan Pepiot, Tampa Bay Rays

Age: 27
ADP: 215

If Shane McClanahan returns in solid form this season, this Tampa rotation could be fearsome with Pepiot and Bradley both having big-time upside behind him. Pepiot had a solid first season as a starter in Tampa, but he flashed some positive signs in the second half of the season as compiled a 2.95 ERA over the final few months (compared to the 3.95 ERA he had in the first half).

Pepiot's fastball averages 95 MPH but has above-average iVB (induced vertical break) and his best offspeed pitch is his changeup which he throws around 85 MPH. The changeup had a 56 percent GB% and 26.2 percent CSW%. All four of his pitches had a Stuff+ rating of 100 or better with his four-seamer at 108 and changeup at 109.

As noted here, Pepiot made a major change to his arsenal in the second half, drastically reducing his slider usage in favor of his cutter and changeup. He has four quality pitches and like most young pitchers, he has to continue to experiment with how to best deploy them. However, the early returns are good and we know that Tampa has had a lot of success developing starting pitchers. Pepiot has established a solid floor and his ceiling offers the potential for a lot of profit at his current ADP.

Luis Gil, New York Yankees

Age: 26
ADP: 159

If I have to pick another pitcher to be skeptical about from this group, it has to be Gil. While he was dominant at times last year (striking out eight or more hitters in seven starts including a 14-K outing against Chicago), he was still plagued by control issues that have followed him throughout each stage of his career.

For some people, a 12 percent BB% is a non-starter, even if a guy has tremendous strikeout stuff because those walks are going to catch up with you eventually one way or another. Gil has great stuff, but being able to locate all three of his pitches has been his issue.

He has a very live fastball that he throws 97 MPH (107 Stuff+) and a sharp-breaking slider that averages 87 MPH (117 Stuff+) but his changeup is still a work in progress. He gets good movement on the pitch, throwing it 91-92 MPH but had just a 55 percent Str% on it last season, meaning he was throwing it out of the zone too often.

I'm always a little concerned with pitchers who don't have much velocity differentiation on their pitches, too. He's throwing three pitches between 97 and 87 MPH, which allows hitters to stay on time against his pitches, even if they do have really good movement.

Despite pitching to a 3.50 ERA over 151 innings last season, Gil still feels pretty raw and will have to do it again before I'm convinced that he's going to be a high-end starter. Some red flags from his numbers last season concern me - like a 37 percent GB% in a hitter-friendly home stadium and a very lucky .238 BABIP as well. His ADP is a bit high for my liking, I think you are paying a premium here for a guy who still has a glaring control issue when you could be taking this next pitcher instead.

Bryan Woo, Seattle Mariners

Age: 25
ADP: 153

There's a healthy amount of hype surrounding much of the Seattle rotation entering this season, especially for Woo, who enjoyed a breakout campaign in 2024 tossing 121 innings to a 2.89 ERA and 0.90 WHIP.

He sacrificed some strikeouts (K% dropped from 25 to 21 percent) but the improvement in run prevention was well worth it and a sparkling 2.8 percent BB% helped him keep the bases clear and that WHIP under one.

Last year, the left-handed splits worried us, with all of #Mariners Bryan Woo's pitches allowing a .340 wOBA or higher.

Woo's two best pitches against left-handed hitters in 2023 were the four-seamer (.345 wOBA) and slider (.344 wOBA). However, the results improved against all… pic.twitter.com/guaXR4QEVQ

— Corbin (@corbin_young21) February 20, 2025

As Corbin notes in the thread above, one of the biggest concerns coming out of his 2023 rookie campaign was the dramatic splits that he had against lefties, but he closest that gap down in a big way last year to where he was nearly as effective to lefties as he was to righties.

As the season went along, he began to mix in more of his secondary offerings (slider, sweeper, and changeup) and was much less of a two-pitch guy as a result. His slider has one of the better Stuff+ ratings in baseball (121) and his fastball, even at just 95 MPH (I know "only 95" is a thing we have to say these days) was an excellent pitch with a 108 Stuff+ rating and a 16.1 percent SwStr%.

Woo has all the tools to become an elite pitcher and we saw a glimpse of it last season. The sky is the limit as this young pitcher could really morph into an ace if he continues to perfect his arsenal and hone his craft.

Spencer Schwellenbach, Atlanta Braves

Age: 24
ADP: 101

I think Schwellenbach is on just about everyone's "sleeper" list this preseason, which makes him, well...not so much of a sleeper. I think the hype is justified, however. Schwelly carried a 20.8 percent K-BB% last season demonstrating some serious strikeout stuff while also flexing some impressive control. His Location+ of 109 was one of the better marks in the league and it's not often we see a rookie with such good control of his stuff. His Pitching+ rating of 113 was the sixth best in all of baseball among starters with 100 innings last year.

Among rookie SP in the second half of 2024 Spencer Schwellenbach ranked:

86 K’s- 1st
2.73 ERA- 3rd
5 Wins- 2nd
79 IP- 1st
0.975 WHIP- 3rd
6.62 SO/BB ratio- 1st

The Braves have another budding ace in the making 💥pic.twitter.com/REoTDgIQel

— Ben Weaver (@weaver_cards) January 14, 2025

There are no red flags here either. His ERA indicators are all within a quarter of a run from his ERA and nothing stands out about his BABIB, HR/FB%, or LOB% that suggests negative regression. If you want to get picky, he had some wide splits (.258 AVG and .438 SLG vs. lefties compared to .200 AVG and .345 SLG vs. righties) but I think most pitchers would be happy to take those numbers against lefties if they could be that dominant against righties.

Everything points to a huge year from Schwelly if he takes another step forward. I wouldn't normally endorse a guy who's getting steamed up this much, but I firmly believe he's the real deal.

Clarke Schmidt, New York Yankees

Age: 28
ADP: 225

Schmidt is a bit of a polarizing name in fantasy circles as he has his backers in addition to plenty of non-believers. While he posted some of the best numbers of his career last season, he did so in just 85 innings and 16 starts so the question remains whether or not he can do it for a full season.

The good news is that his pitches all graded out better in terms of Stuff+ than they did in 2023 and around the same levels from 2022. His best pitches are his cutter (104), slider (110), and curveball (121). His two-seamer is still by far his worst pitch, but he threw it less often last season and would be wise to possibly phase it out even more going forward or replace it with a four-seam fastball.

He might be nursing an injury to start training camp, which is less than ideal, but if he's healthy and ready to go this year, I think he's well worth targeting based on the ability he showed last year to strike out hitters (26 percent) while also demonstrating solid run prevention. He's not going to be a sub-3.00 ERA guy, but his ERA indicators were all still well under 4.00 and he has a great shot at racking up wins for a Yankees team that is a World Series contender once again.

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