Best Minor League Sliders & Curveballs Per Stuff+ In 2025

Image credit:
Cam Caminiti (Mike Janes/Four Seam Images)

Yesterday, we examined the top fastballs in the minor leagues per Stuff+, ranking the top four- and two-seam fastballs as graded based on their unique pitch characteristics.

Today, weâ€ll be continuing our Stuff+ series by taking a look at a pair of breaking balls shapes in sliders and curveballs.

When it comes to breaking balls, it’s important to remember that we see a wider spectrum of shapes than we did in four- and two-seam fastball categories from yesterday. As such, for our purposes, weâ€ll be excluding sweepers and cutters. That’s because there is a large chunk of the sweepers that are identified as sliders and curveballs by ball-tracking systems, while many cutters get categorized as fastballs.

Taking into consideration factors like velocity, vertical movement, horizontal movement, extension and release height, Stuff+ grades begin at an average of 100 and move up or down the scale to communicate whether a pitch has above- or below-average “stuff.” The grading is specific to each pitch type, allowing us to directly compare sliders to other sliders, and so forth. 

To be included in this exercise, pitches needed to be thrown a minimum number of times this season based on average usage rates for each pitch type. Note that sliders have a higher usage rate than pitches designated as curveballs. Scores are based on an internal variation of Stuff+ engineered by Dylan White. 

Slider Stuff+ Leaders (Min. 250 pitches)

playerorghandgradeJohan SimonTORL135Gerelmi MaldonadoSFGR132Jefferson JeanOAKR130Niko MazzaSFGR130Cam CaminitiATLL130Joel PegueroSFGR129Andrew PainterPHIR129Hunter OmlidCOLR129Ryan SloanSEAR129Titan Kennedy-HayesPHIR128Evan GraySFGR127Brandon ClarkeBOSL127Luis MoralesOAKR127Peyton OlejnikLAAR127Jarlin SusanaWSNR126Carlos LagrangeNYYR126Christian OpporCHWL126Jostin FlorentinoCHCR126Noah SchultzCHWL125Tyson HardinMILR125

• The top slider per our Stuff+ metric belongs to the Blue Jays’ Johan Simon. The pitch is a low-to-mid-80s sweeper with around four to five inches of ride and 12-13 inches of sweep on average. It really stands out for its unusual horizontal approach angle of 4.39 degrees, which is a product of Simonâ€s low three-quarters arm slot that helps all of his stuff play up. After spending parts of three seasons in the Florida Complex League, Simon ascended to Double-A New Hampshire by the end of 2025.

• The Giants’ Gerelmi Maldonado continues to blow up Stuff+ models, thanks in large part to his plus slider. A true two-pitch pitcher, Maldonado only threw fastballs and sliders in 2025. His slider sits 83-85 mph with true sweeper shape and averages 11-12 inches of sweep from an outlier horizontal approach angle of -3.8 degrees. Itâ€s a higher-spin offering for a sweeper, as he averages 2600 to 2700 rpms.Â

• Cam Caminiti performed well in his first full professional season, as he made 13 starts with Low-A Augusta and pitched to a 2.08 ERA while boasting one of the top sliders in the lower minors. His slider is a sweeper with between 4-6 inches of ride and 10-11 inches of sweep. Caminiti also has an outlier HAA of -4.9 degrees, which helps to play up movement on the pitch. The 19-year-old lefthander showed good command of the pitch and missed a high rate of bats in the zone with it, but it didnâ€t generate as many chase swings as one would expect.Â

• Despite a disappointing season for Andrew Painter in his return from Tommy John surgery, the Phillies righthander boasts some of the best secondary stuff of any pitcher in the minors. His upper-80s cut-slider grades out extremely well on Stuff+ models, as he balances premium velocity, movement and release traits. The pitch misses fewer bats than expected (30.5% whiff) but drives weak contact consistently.Â

• Seeing fireballers Carlos Lagrange and Jarlin Susana included on this list shouldn’t come as a shock. Both mix hard sliders sitting in the 86-90 mph range. Susanaâ€s slider generates more sweep, while Lagrangeâ€s generates more cut. Each are powerful secondaries that play off triple-digit fastballs.Â

• One of the more intriguing lower-level pop-up arms this season is Jostin Florentino of the Cubs. Over 10 starts with Low-A Myrtle Beach, Florentino pitched to a 1.96 ERA with a 26.9% strikeout rate. His slider was a big reason for his success this season, and it grades out very highly on our internal model. The pitch shows below-average velocity in the mid 70s, but gets outlier spin traits, averaging between 2700-3000 rpm with an average 18-20 inches of sweep. Florentinoâ€s impressive combination of movement and spin is enough to overcome the lack of velocity for now. Itâ€s a truly unique pitch with an outlier HAA of -4.5 degrees, which helps it drive excellent whiff and chase rates.

• If you like your pitchers with a blend of swagger and stuff, allow me to introduce you to the Phillies’ Titan Kennedy-Hayes. The Phillies’ 2024 11th-rounder out of Austin Peay, he made 40 appearances between Low-A and High-A this year. His slider is eye-popping, as itâ€s an 87-89 mph sweeper with an average of 9-11 inches of horizontal break and spin rates in the 2600-2800 rpm range. Kennedy-Hayes had a so-so season, but his slider might be enough to carry him to the big leagues in the coming seasons.Â

• Few players had as much helium over the first two months of the season as Red Sox lefty Brandon Clarke. And though a recurring blister issue kept him limited for large chunks of the season, thereâ€s no denying the supreme quality of Clarke’s slider. Itâ€s a high-80s sweeper with outlier extension (7-foot-1) and an oddity HAA that allows the pitch to play up.Â

• Christian Oppor and Tyson Hardin were two of the biggest out-of-nowhere breakouts in 2025, with both riding the quality of their pitch mixes and sliders to success at each stop. Hardinâ€s slider is a low-to-mid-80s sweeper that averages 11-13 inches of horizontal break. Oppor, meanwhile, boasts a similar shape just a few mph softer than Hardinâ€s. Each did a good job of driving whiffs, though Hardin shows better pure command of his pitch.Â

• Jefferson Jean and Noah Schultz also showed up in our fastball Stuff+ rankings, which makes their lack of success all the more puzzling. Both struggle with execution in different ways, but they still have some hope going forward if they can master their command.  Â

Curveball Stuff+ Leaders (Min. 200 pitches)

playerorghandgradeChance HuffWSNR122Niko MazzaSFGR120Thomas WhiteMIAL119Yosber SanchezDETR117Jordany VenturaNYYR117Andrew PainterPHIR116Evan FittererMIAR116Tyler BryantMILR115Brody HopkinsTBRR115Zac LeighCHCR115Pierce GeorgeCHWR114Drew BeamKCRR114George KlassenLAAR114Victor ZarragaCHCL114Angel JimenezCOLR114Cristian MenaARIR114Juan ReynosoMIAR114Moises MoralesTEXR113Daury VasquezARIR113Adam SerwinowskiLADL113

• Drafted in the eighth round in 2022 out of Georgia Tech, Chance Huff enjoyed a breakout campaign in 2025, as he made 35 appearances for Double-A Harrisburg and pitched to a 3.54 ERA while striking out 47 batters across 56 innings. Huffâ€s curveball is the highest-graded in our model that was thrown a minimum of 200 times this year. Itâ€s a slurvy, mid-to-high-80s offering with negative induced vertical break and around 8-10 inches of sweep.Â

• It can be argued that the Marlins†Thomas White is the top pitching prospect yet to make his MLB debut, and his quality secondary stuff is a big reason why. Whiteâ€s curveball is a sweeper with negative vertical break that gives it two-plane depth. The pitch is one of White’s best-commanded offerings, boasting high strike and zone rates. The 21-year-old lefty has shown the ability to miss bats with the pitch both in and out of the zone, even against higher-minors competition.Â

• After earning praise in our fastball rankings, the Rays’ Brody Hopkins makes an appearance in our breaking ball rankings thanks to his outlier curveball. Hopkins might boast the most impressive Stuff+ arsenal in the game, with his curveball maybe being the best pitch of the bunch. The pitch sits 88 mph with true downer curveball shape, and its combination of power and movement make it among the best traditional curveballs thrown in the game today. The results speak for themselves, as Hopkins shows advanced command of the pitch with the ability to drive whiffs in and out of the zone:

Strike%InZone%Miss%Chase%69.70%43.90%42.70%50.00%

• The Brewers signed righthander Tyler Bryant out of the independent Frontier League in June 2024. He spent all of 2025 with Double-A Biloxi, where he showed off one of the best curveballs in the minors. Bryantâ€s primary breaking ball is a two-plane banger with 8-9 inches of negative induced vertical break and 10-12 inches of sweep. He generated a 46.8% whiff rate against it this season, helping to produce a strong grade in our internal Stuff+ model. Â

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