Nine Fantasy Baseball Prospect Risers - Dynasty Gems In High-A

June 4, 2026

Andersen's fantasy baseball prospect sleepers, risers, stashes currently in High-A. His fantasy baseball dynasty gems and breakouts to target in dynasty leagues.

With nearly two months of MiLB data already collected this season, it's time to begin identifying the most promising prospects at the High-A level who have seen their value increase. While some of these prospects may already be rostered in many dynasty leagues, other prospects remain under the radar and likely represent high-upside stashes in most formats.

Below, we will highlight nine prospects who have turned in a strong first two months at the High-A level, including a pair of Chicago Cubs and a budding outfield star in Atlanta.

Let's take a look at nine dynasty risers at the High-A level that you should either stash in your dynasty league or acquire via trade before they begin to showcase this upside at the Double-A level.

Devin Fitz-Gerald, INF, Washington Nationals

The Rangers selected Fitz-Gerald in the fifth round of the 2024 MLB Draft before sending him to the nation's capital as part of last offseason's MacKenzie Gore trade. An advanced hit tool is Fitz-Gerald's top trait, but he also runs well enough to steal 11 bases through 46 games this year. Defensively, he's capable of playing second, short, or third, but second base projects as his long-term home.

This year, Fitz-Gerald is slashing .291/.400/.582 with 12 homers and 152 wRC+. There's minimal whiff in his game, as he ranks in the 86th percentile in whiff rate, zone contact rate, and strikeout rate.

At 5-foot-10 and 185 pounds, it remains to be seen whether Fitz-Gerald's power will persist as he reaches the upper levels of the minors. At the very least, though, his speed and contact skills give him the potential to be a significant threat for extra-base hits and stolen bases in fantasy baseball.

Devin Fitz-Gerald has been a force at the plate over the last 30 days...

112 PA
.309 AVG
.414 OBP
.755 SLG
19 XBH
10 HR
28 RBI
17 BB
14 K#Natitudepic.twitter.com/m98fYqHjRl

— Eric Cross (@EricCrossMLB) May 28, 2026

Mavis Graves, SP, Philadelphia Phillies

Graves was a sixth-round pick in the 2022 MLB Draft. He has shoved at every level of the minor leagues he's been in, and at 22 years old, he could be on a fast track for promotions to Double- and Triple-A.

The 6-foot-6 southpaw sits in the low-90s with his fastball. While the velocity might be subpar for a pitcher of his size, the offering has plenty of sink and induces a high rate of groundballs. There's a wide range of spin in his profile, as he throws an effective low-spin changeup but can also get his slider up near 3,000 rpm. He rounds out his repertoire with a cutter.

This year, Graves has a 3.41 xFIP with 13.24 K/9 and 3.63 BB/9. He gets a ton of chase (86% out-of-zone swing rate) and misses (41.9% whiff rate), and his stuff should continue to play at the next level. The 1.04 HR/9 rate isn't ideal, but his ability to rack up high rates of strikeouts and groundballs should allow him to be an effective arm in fantasy baseball down the road.

Ty Southisene, SS, Chicago Cubs

The brother of Braves first-round pick Tate Southisene, Ty Southisene, has started making headlines of his own. A fourth-round pick in 2024, the elder Southisene checks in at 5-foot-7 and is a major speed threat, swiping 22 bags through 45 games this year.

There's minimal power in Southisene's game, as he has yet to hit a home run through 136 career minor league games. However, in addition to being quick, the 20-year-old is a crafty contact hitter who gets on base and uses his speed to create runs. Despite hitting zero home runs, he owns a 129 wRC+, largely thanks to his 12.2% walk rate (61st percentile) and 9.0% strikeout rate (100th percentile).

This year, Southisene has posted a 22.1% out-of-zone swing rate (78th percentile), a 20.5% whiff rate (88th percentile), and a 90.6% zone contact rate (97th percentile). He has tremendous fantasy upside and is comparable to a Nico Hoerner with even more speed.

Josh Adamczewski, OF, Milwaukee Brewers

The Brewers selected Adamczewski in the 15th round of the 2023 MLB Draft. At the time, he was an intriguing prep infield prospect, but he has transitioned to playing almost entirely in left field at the High-A level this year.

Through 41 games, Adamczewski owns a .306/.451/.537 slash line with seven homers, eight steals, a 20.2% walk rate, and a 19.7% strikeout rate. The walk rate is his biggest outlier metric, ranking in the 92nd percentile and signaling a fantastic ability to get on base. We'd like to see him be a little more aggressive than his current 43.5% swing rate, but we're obviously impressed by his 22.2% out-of-zone swing rate.

The organizational fit here is very encouraging. The Brewers have a certain type of prospect they target, and Adamczewski fits their brand of baseball: versatile defenders who get on base and hustle enough to create runs with steals and extra-base hits. We wouldn't be surprised to see him in the majors in 2027 or 2028.

Nolan Perry, SP, Toronto Blue Jays

The Blue Jays selected Perry with their 12th-round pick in the 2022 MLB Draft. The prep prospect from Carlsbad High School in New Mexico fetched a $200,000 signing bonus, luring him away from his commitment to Texas Tech. A 2024 Tommy John surgery aside, that investment appears to have paid off for the Jays.

Following his surgery, Perry has added velocity to his fastball, which now sits around 94 mph. He throws a breaking ball (an average slider or his superior curveball) 50% of the time, and he rounds out his repertoire with a changeup that kills spin. The right-hander is an advanced metrics hero, posting a 37.6% whiff rate, 34.3% out-of-zone swing rate, and 63.2% strike rate.

In his first year back from injury, Perry owns a fantastic 1.37 ERA. While ERA isn't everything — and his FIP is admittedly a little higher at 2.56 — we're highly encouraged by Perry's progression and could see him emerging as a high-priority waiver wire target for fantasy baseball managers in the middle of the 2027 season.

Eric Hartman, OF, Atlanta Braves

Hartman is one of the biggest prospect risers this year. A 20th-round pick out of high school in 2024, Hartman has overcome his low draft stock to become one of the top offensive contributors in High-A.

Speed is Hartman's calling card, but we're impressed by the hit, power, and fielding tools, too. Through 47 games this year, he's slashing .296/.373/.581 with 13 homers, 18 steals, and 147 wRC+. His 77.7% zone-swing rate is one of the best in High-A, but he can occasionally get too aggressive and chase out of the zone, too.

It will be important to see how Hartman's slight chase problem progresses as he faces more crafty pitches at the higher levels of affiliated ball. If he can keep his chase rate at the same level (or lower), he has a high probability of developing into an impactful power/speed threat for fantasy baseball managers in a few years.

Eric Hartman in High-A this season...

37 GP, 170 PA
.315/.395/.658
37 Runs
10 Doubles
13 Home Runs
33 RBI
16 Steals

Absolutely skyrocketing up prospect rankings.#BravesCountry pic.twitter.com/hzbHcVhNNW

— Eric Cross (@EricCrossMLB) May 21, 2026

Brooks Auger, SP, Los Angeles Dodgers

It wouldn't be a prospects article without a Dodger, would it? Auger was Los Angeles' sixth-round pick in the 2024 draft. One of many college arms the Dodgers have taken over the last two years, the right-hander is always a threat to strike out batters, and he does so while limiting walks and loud contact.

This season, Auger owns a 3.20 ERA, 1.50 FIP, 15.10 K/9, 2.75 BB/9, and 0.00 HR/9. He doesn't induce a ton of groundballs, but he limits hard-hit balls and generates plenty of whiffs (31.3%). His fastball sits in the mid-90s, and he also throws a slider, curveball, and changeup. Together, the pitches in his arsenal have led to a very impressive 67.6% strike rate and 31.6% out-of-zone swing rate in 2026.

We'll see whether Auger's success can be sustained at higher levels of the minors if his ground-ball rate stays low. We're tempted to bet on his success, though, as the high chase and low hard-hit rates typically suggest a pitcher will be able to handle better competition. Already 24 years old, Auger could be ready for the majors early in the 2027 season.

Kane Kepley, OF, Chicago Cubs

The Cubs used their 2025 second-round pick on Kepley, an outfielder from the University of North Carolina. After a solid season in Chapel Hill, the 5-foot-8 outfielder fetched a $1.4 million signing bonus from the Cubs. He debuted at Single-A last year and has spent all of 2026 at High-A, delivering a high stolen base total.

Kepley isn't very aggressive, but this low-swing approach has allowed him to minimize his chase and strikeout rates. His out-of-zone swing rate (17.4%) and whiff rate (15.4%) both rank in the 98th percentile, and he makes contact on nearly 90% of pitches in the zone. He owns a 131 wRC+ this year with a 20.6% walk rate, 13.9% strikeout rate, and a whopping 29 steals through 44 games.

Kepley has just four homers through 72 career minor league games, so he doesn't offer the Cubs much power. However, he makes up for it with his ability to make contact, get on base, and pick up extra bases via steals and hits to the gap. The baserunning alone should be enough to generate fantasy appeal once he reaches the majors in a couple of years.

Kash Mayfield, SP, San Diego Padres

Mayfield is a 6-foot-4 southpaw who landed with the Padres in the first round of the 2024 MLB Draft. He signed for nearly $3.5 million out of high school, representing a big pitching investment for the Padres. So far, he's been worth every penny, and it looks like San Diego might have a long-term starter in its pipeline.

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