Top 20 Fantasy Baseball Prospects - Dynasty Fantasy Baseball Prospect Rankings: September Update

September 24, 2026

Andy's top 20 fantasy baseball prospect rankings for MLB prospects in the minor leagues. His September 2026 dynasty prospect rankings for fantasy baseball.

Hey RotoBallers! Welcome to the final of my monthly top-20 non-debuted prospect rankings. The 2026 MLB and MiLB seasons are wrapping up, but that doesn't mean we don't have one final top-20 prospect update. As always, this top-20 list consists of prospects who have not made their MLB debuts.

Over the past month, future superstar Josue De Paula joined Walker Jenkins and Ethan Salas in the big leagues, opening the door for some new faces to crack the top-20. Even though De Paula's time in Los Angeles is just getting started, he won't be considered for this list since he stepped onto the MLB diamond.

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Top-20 Non-Debuted Prospects: September Update

Honorable Mentions

Hitters:

• Seaver King
• Alfredo Duno
• Luis Pena

Pitchers:

• Travis Sykora
• Thomas White
• Jackson Flora
• Cam Caminiti

Dynasty Fantasy Baseball Prospect Outlooks

Franklin Arias, SS, Boston Red Sox

Franklin Arias had a dominant season in the upper minors but hasn't yet reached the major leagues. Arias began the 2026 season at Double-A, where he posted a .318/.407/.58 line with a stellar .994 OPS. Arias went deep 19 times, which not only set a career high at the time, but did so in dominant fashion.

Entering the 2026 season, Arias had only hit a season-best nine home runs in 87 games over the lower levels.

This strong performance earned him a ticket to Triple-A Worcester, where the budding superstar continued to rake.

Through his first 42 games at the top club, Arias held a .331/.388/.506 line with 11 doubles, six home runs and four stolen bases. Despite facing tougher pitching, Arias' K% only increased by one point (13.9% to 14.9%) while his walk rate slightly dipped from 11.1% to 8.5%.

The lone concern in his underlying profile is that his fly-ball rate dropped by 10 points since moving to Worcester, which is likely why the Red Sox were hesitant to give him the call, but his stable walk and strikeout rates are a promising sign nonetheless.

A strong spring training should push Arias to the major leagues quite early in the 2027 season and potentially on Opening Day. Among the non-debuted prospects on the list, Arias is likely to be one of the top names on fantasy draft boards next spring.

Red Sox top prospect Franklin Arias had a breakout year 🔥

.323 AVG
25 HR
91 RBI
.957 OPS

Arias was named Eastern League MVP in Double-A and finished the season as MLB's No. 3 prospect! pic.twitter.com/dsphMHrlcg

— MLB (@MLB) September 22, 2026

Anthony Eyanson, SP, Baltimore Orioles

Eyanson was a former Boston prospect but was shipped to the Orioles ahead of the trade deadline in the deal that sent Adley Rutschman to the Red Sox. Eyanson began the campaign at the High-A level but has since moved up to Double-A, which puts him in prime position to compete for a second-half debut in 2027.

At High-A, Eyanson was making headlines, logging 20 1/3 innings to the tune of a near-perfect 0.44 ERA and a 0.44 WHIP. He struck out 34 hitters while serving up only three total walks. This dominant play earned him a ticket to Portland, where he looked just as dominant, posting 48 frames with a 1.69 ERA and a 1.01 WHIP.

Since moving to Chesapeake (the Double-A club in the Baltimore system), Eyanson has held a 2.03 ERA with a 1.10 WHIP over 31 innings. In total, the right-hander has logged 99 1/3 innings in 2026 (his first professional season) with a 1.54 ERA, 0.96 WHIP, and a 107:32 K:BB.

Per FanGraphs, Eyanson boasts a 55-grade fastball with three secondary offerings (slider, changeup, and curveball), all with a 60-future grade. With above-average stuff, upside, and command, Eyanson has the talent to progress through Norfolk rather quickly.

Gage Wood, SP, Philadelphia Phillies

The other pitcher to slide into our top-20 is Gage Wood of the Phillies. Like Eyanson, Wood remains on a clear trajectory to debut with his MLB club in 2027 but has not been as dominant since joining the Double-A level. Wood made his pro debut in 2025 but logged only two innings, making him nearly a first-year pitcher in 2026.

He began the campaign with Low-A Clearwater, where he needed only 26 1/3 innings to prove he was ready to earn the call to Double-A, skipping High-A in the process. At Low-A, Wood struck out 40 batters over this stint while holding a 3.42 ERA.

However, since joining Double-A, Wood's face-value stats have taken a slight dip. Through his first 68 2/3 innings, Wood has posted a modest 4.72 ERA but has continued to flash high-end strikeout potential, totaling 99 (at a 33.1% rate). But that doesn't tell the full story.

Under the hood, Wood has generated a 3.05 xFIP, which is nearly an entire point lower than his surface-level 4.37 FIP (at Double-A), suggesting he should see some significant positive regression in 2027. Additionally, he has lowered his walk rate from 11.4% to 6.0% since moving to Double-A, further showcasing his steady development.

Wood has a 70-grade fastball with an emerging curveball that could become his go-to secondary offering. Wood has elite strikeout potential and has the upside to make an immediate fantasy impact as soon as he reaches Philadelphia.

Ninth strikeout of the night ties a career-high for Gage Wood 👀 pic.twitter.com/9Kzh8OuxfG

— Reading Fightin Phils (@ReadingFightins) September 3, 2026

Rainiel Rodriguez, C, St. Louis Cardinals

Let's get back to some hitting prospects. Once again, the lone catcher in my top-20 is Cardinals backstop, Rainiel Rodriguez. Rodriguez has yet to slow down since making his debut and has emerged as one of the top power hitters in all of the minor leagues.

After posting a .311/.430/.519 line with High-A (over 28 games), Rodriguez has since spent the majority of the 2026 season with Double-A Springfield. At this level, the backstop has launched 23 home runs over 87 games with a stellar .328/.408/.591 line. He has added 22 doubles and even swiped seven bags.

Since moving to Double-A, Rodriguez has seen his ISO increase to .254 (from .208 at High-A) while maintaining a sub-20.0 % K% with a double-digit walk rate. Rodríguez has also raised his pull rate to 45.4% and lowered his ground-ball rate despite facing tougher pitching. The 19-year-old could make an immediate impact for fantasy as soon as he earns the call.

Rodriguez should be a strong candidate to earn the call to Triple-A early in the 2027 campaign.

Josuar Gonzalez, INF, San Francisco Giants

Let's conclude our list with two of the top shortstop prospects in the sport. Gonzalez is only 18 years old but has the potential to be a borderline top-5 prospect as he progresses through the San Francisco system. The infielder made his professional debut in 2025 in the Dominican Summer League but only made his stateside debut in 2026.

He joined Low-A San Jose earlier this season and has since appeared in 31 games. Over this short stint, the infielder has held a dominant .357/.444/.566 slash line with six doubles, six triples, three home runs and 13 stolen bases. He has carried a sharp 30:21 K:BB. Earlier this summer in the DSL, Gonzalez showed a similar eye, posting a 25:20 K:BB over 30 games while posting a .966 OPS.

While his MLB debut is still many seasons away, Gonzalez is a name to keep a close eye on in dynasty leagues. Per FanGraphs, the infielder has a 50-grade future score in hitting, and a 55 future grade score in raw power to pair with his already above-average speed.

The "buy" window for those in dynasty formats is closing quickly as Gonzalez could begin the 2027 season at High-A.

Sebastian Walcott, SS, Texas Rangers

The final name we will spotlight in this edition spent most of the 2026 season injured. Sebastian Walcott underwent a UCL operation, which kept him on the shelf until mid-July. However, before that operation, Walcott was making impressive strides in the Rangers system and was making a strong case to join the elite tier of budding prospects.

Once cleared to return, he was sent to Double-A, where he quickly made an impact. Through 37 games with Frisco, the shortstop would post a .322/.398/.586 line with a .984 OPS, which was a massive jump from the .785 OPS he held throughout most of the 2025 season at the High-A level. During this stint, Walcott hit 13 doubles with nine home runs and even swept 11 bags.

This dominant play earned him a late-season start in Triple-A, where he went 2-for-8 with a stolen base. If Walcott did not miss the entire first half, there is a strong possibility he could have been in Texas for the Wild Card run.

He is a name to watch in spring training, as a strong camp could set him up for an early debut in 2027, like Arias.

MLB's No. 9 prospect Sebastian Walcott (@Rangers) legs out his first Triple-A hit for the @RRExpress! pic.twitter.com/QWYEaVvU7a

— MLB Pipeline (@MLBPipeline) September 20, 2026

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