Top 100 Fantasy Baseball Prospects - Dynasty Rankings for Non-Debuted Prospects (September Updates)

Kevin's updated top 100 fantasy baseball prospect rankings for MLB prospects yet to debut in the majors. His August 2025 dynasty prospect rankings for fantasy baseball.

It's time for another update to my dynasty fantasy baseball prospect rankings for September of the 2025 season. Since the last prospect rankings, we've had quite a few call-ups in the Top 100. This is because rosters have expanded in September, and prospects can make their debuts while keeping their rookie eligibility for next season.

This will be my last big prospect update of the 2025 season. The next one will be before next season. This fantasy baseball prospect rankings list will only have non-debuted prospects. I'm also resharing some of my general prospect ranking philosophies for those who are new to my rankings.

• Upside over proximity: the best prospects are often closer to the majors than they seem, and the low upside guys will always have factors that block their chances of being too fantasy relevant
• I will probably be lower on your favorite pitching prospect than most lists: I've just seen this film before, and I didn't like the ending too many times
• I am a sucker for age-to-level production- there's a reason why the top NBA draft pick every season is a college freshman or teenager playing overseas against grown men. A similar analysis can be utilized to value baseball prospects
• What you did as an amateur matters very little to me once you have a solid sample size of professional games under your belt

Fantasy Baseball Prospect Dynasty Rankings: Top 100

Prospect details can be found in the rankings table below, with some thoughts on a few exciting prospects.

Regarding risers and fallers, some prospect risers and fallers have tangible things they've done since the last ranking to justify that change.

However, some risers and fallers are just me recalibrating my thoughts on a prospect. I won't hesitate to adjust a player's ranking, even if it might make my previous ranking "look bad". Let's get to it:

No. 19: Rainiel Rodriguez, C, St. Louis Cardinals

I wrote about Rodriguez as a big riser in my last update, and he has just continued to mas,h so I had to push him into my Top 20.

Between the Complex and Low-A this season (and one game at High-A), Rodriguez has a 164 WRC+ with 20 HRs. He's also only striking out 17.5 percent of the time while walking 15.0 percent of the time. 18-year-olds that can hit for this much power while maintaining strong plate discipline stats like this don't come around that often.

Rainiel Rodriguez had three hits in his High-A debut yesterday and has been a big riser in prospect rankings this season.

356 PA, .280/.407/.567, 21 2B, 20 HR, 15.2% BB, 17.7% K

Rodriguez is now one of the top catching prospects in the game.pic.twitter.com/HLnPDm1Qad

— Eric Cross (@EricCrossMLB) September 5, 2025

It's rare for prospects that don't provide speed to get to Top 10 status, but Rodriguez's bat is impressive enough that he could be there soon if he continues to rake.

No. 32: Emil Morales, SS, Los Angeles Dodgers

Morales came into the season with quite a bit of hype after he had a great 2024 season in the DSL. He had the second-highest WRC+ in the level at 186, only behind Rodriguez. He hit for a lot of power with 14 HRs and had a solid approach at the plate, striking out only 22.4 percent of the time and walking 19.9 percent of the time.

However, when he started up his career stateside this season, he was solid but didn't light the world on fire. At the Complex, he had a 127 WRC+, but his K-rate spiked to 28.3 percent.

He got promoted to Low-A about a month ago and has been on fire since. At only 18 years old, he has a 162 WRC+ with five HRs and four SBs in 133 PAs since getting the bump. He's also lowered his K-rate to a more palatable 23.3 percent while maintaining the BB-rate he had at the Complex (11.3 percent).

Emil Morales had three hits last night for Rancho and walked once, so he was on base four times and scored a couple of times as well.

Morales has skyrocketed his average to .356 as a Quake, OPS of 1.051. He has hits in 9 games in a row, he has back-to-back multi-hit games, and 6… pic.twitter.com/tIIaL6cMPg

— Dodgers Daily (@dodger_daily) August 27, 2025

Over the last month, Morales has shown the upside he flashed in the DSL last season. He has the potential to be a Top 25 prospect soon.

No. 38: Alfredo Duno, C, Cincinnati Reds

Another massive Low-A riser has been Duno. I think he would be getting even more hype if another NL Central power-hitting catching prospect weren't stealing the spotlight from Rodriguez.

He could've broken out last season in his first season stateside, but his season was cut short due to injuries, and he only played in 32 games at Low-A. He's repeating Low-A this year at 19 years old, and he's been excellent all season. He has a 162 WRC+ with 17 HRs, and he's walking (18.9 percent) more than he's striking out (18.3 percent).

Over the last month, he's been one of the best hitters in the minors and could be forcing his way to get a taste of High-A. He also just gave a rude professional baseball welcome to one of the top pitchers in this latest draft, Liam Doyle.

The second batter that Doyle faces, Alfredo Duno, crushes a homer hahahahahahahaahha ahhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh
Duno is leGit though. Slider in the middle yuck pic.twitter.com/Ffs5IaDMCo

— Kyle Reis, 58% Neanderthal (@kyler416) September 6, 2025

It's always exciting for a young catcher to flash this kind of power upside. If he can maintain the plate skills that he's shown this season, he'll be getting a lot of buzz across the industry.

No. 64: Robby Snelling, P, Miami Marlins

Coming into 2024, Snelling was viewed as one of the top pitching prospects in the sport. In 2023, he had a 1.82 ERA and 20.2 percent K-BB rate across Low-A, High-A, and Double-A at just 19 years old. With how aggressive the Padres are, it seemed like Snelling could be a few solid months away from getting the call to the majors at only 20 years old.

However, he struggled immensely in 2024. In Double-A with the Padres organization, he had a 6.01 ERA with a 10.3 percent K-BB rate. As the Padres do, they pulled the plug on Snelling quickly and shipped him to the Marlins as part of a deal for Tanner Scott.

The Marlins' pitching factory did what they do, and Snelling started to look better after getting traded. He had a 3.64 ERA and 20.3 percent K-BB rate in 42 innings with the Marlins in Double-A and Triple-A. He still did have a bit of stink on him, given how bad things ended with the Padres.

In 2025, Snelling is looking like the stud we saw a couple of years ago. He has a 2.66 ERA and 23.1 percent K-BB rate in 125 innings between Double-A and Triple-A. Since getting the bump to Triple-A, he's been absolutely lights out.

Robby Snelling just went the distance in a 7 inning game striking out 13, walking nobody and allowing just one earned run.

He entered today with a 1.25 ERA over his last 10 starts, 8 of which at Triple-A. You can sharpie him into the Marlins rotation for next year. pic.twitter.com/YB9jMfeSGK

— Aram Leighton (@AramLeighton8) September 3, 2025

I've moved Thomas White to the top of my pitcher prospect rankings. He and Snelling should give Marlins fans a lot to be excited about next season.

No. 69: Ralphy Velazquez, 1B, Cleveland Guardians

For most of the last year, I've viewed Velazquez as a fine but unspectacular prospect. He was solid in 2024 with a 117 WRC+ between Low-A and High-A as a 19-year-old. He also got off to a pretty good start in High-A this season with 17 HRs and a 119 WRC+.

However, over the last month, since he got the bump to Double-A, he has been one of the best hitters in the minor leagues. In 91 PAs at the level, he has a 220 WRC+ with five HRs. He has also dropped his K-rate to 14.3 percent, whereas he had struck out over 20 percent of the time at every level since the Complex in 2023.

Ralphy Velazquez dominated this month 🔥

He's slashing .366/.478/.677 with seven homers in his last 24 games.

More hitting prospects with standout data in August: https://t.co/NhErerMmk6 pic.twitter.com/hDh1rZR03G

— Baseball America (@BaseballAmerica) August 30, 2025

While you generally don't want to overreact too much to such a small sample, it's hard to ignore how good Velazquez has been since getting promoted to Double-A. If he can keep this up throughout the end of the season, he could be looked at as a top 50 prospect going into the offseason.

No. 74: Nelson Rada, OF, Los Angeles Angels

Rada is the Moneyball meme for me in that I like so much about him- he just has no power. He has extremely impressive age-to-level production, and he will steal a lot of bases.

The Angels have pushed Rada extremely aggressively (on brand) as he's already in Triple-A and just turned 20 a couple of weeks ago. However, he has met the challenge with every aggressive assignment.

He has a 124 WRC+ between Double-A and Triple-A this season while striking out under 20 percent of the time. He also has 51 SBs. However, he has only two HRs after hitting only one last season.

Rada doesn't have the cartoon speed that Chandler Simpson has, but he could be one of the better hit-speed prospects we've seen in the last few years for fantasy.

No. 96: Marconi German, 2B/SS, Washington Nationals

Going to preface this segment by saying there isn't a Jesus Made every season to come out of the DSL, and even if there is one, it's not super easy to figure out who it is going to be. However, after the meteoric rise of Made (and Luis Peña), there is going to be a lot of hype around guys who could be the next Made.

In some leagues, you can probably just take multiple shots on potential DSL hype beasts going into the offseason. However, it's more likely that you'll need to make some bets on one or two. If you can make one big DSL bet going into the offseason, perhaps you should bet on German.

I have to give a hat tip to my friend PJ, aka ProspectVibeCheck on Twitter, for putting me on to German. He was one of the first people I saw talking about him, and he had a great thread about him a few months ago.

On first glance, German's DSL campaign does look a bit like Made's. He has a 162 WRC+ while walking (20.2 percent) more than he's striking out (19.7 percent). He also has eight HRs and 33 SBs. He's flashing all of the tools that you want to see from a DSL stud who will make an impact once he comes stateside.

Marconi German has been named a Dominican Summer League All-Star. He did this in his first pro season ⬇️

.283/.479/.513
9 2B, 3B, 8 HR
30 RBI
43 BB
33 SB pic.twitter.com/FCOXCHq2kx

— Nationals Player Development (@Nats_PlayerDev) August 29, 2025

Betting on DSL prospects is a bit like investing in penny stocks in The Wolf of Wall Street. We've seen many DSL studs flame out when they come stateside. However, you can win big on some of these DSL prospects.

Two other DSL prospects in my Top 100 are Josuar De Jesus Gonzalez of the Giants and Elian Peña of the Mets. However, both of these guys got plenty of hype upon signing as they were the number two and three international prospects in the 2025 class (per MLB Pipeline) besides Roki Sasaki, so I'd imagine they have higher price tags.

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