Fantasy Baseball Prospect Risers - Rookies to Stash and Top Performers for Week 19 (2025)

Andy's fantasy baseball prospects sleepers and risers to know for Week 19 of 2025. He analyzes top MLB prospects and rookies to stash based on recent performances.

Welcome, RotoBallers, to my Week 19 edition of the top prospect performers. In this week's piece, we will look at two emerging bats at the Triple-A level and a right-handed pitcher who is producing at an elite level at Double-A.

During the first half, we saw many high-end prospects get the call to the big leagues and make an immediate impact. As we enter the stretch run, it will be critical for fantasy managers to stash the right prospects.

Adding the right prospect can fill the missing piece on your roster and set you up for a fantasy championship. This fantasy baseball prospects monthly series will examine a few key players in the minor leagues and assess whether they have a path to fantasy stardom in 2025. Be sure to follow RotoBaller MLB and me on X for all your fantasy baseball needs this season. Let's get to it!

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Sal Stewart, 2B/3B, Cincinnati Reds

Reds No. 3, Overall No. 51

Cincinnati Reds infield prospect Sal Stewart has quickly progressed through the upper levels of the minor leagues. After spending the 2024 season with High-A Dayton, Stewart was given the green light to start the 2025 campaign with Double-A Chattanooga. With the Lookouts, Stewart posted an impressive .306/.377/.473 slash line with 19 doubles and 10 home runs through 80 games.

During this stretch, Stewart swiped 13 bags, scored 51 runs, and brought in 44 RBI. He held a 51:27 K:BB.

However, in a surprising move, early this month, the Reds opted to promote Stewart to Triple-A Louisville. Even though he was looking quite comfortable at Double-A, since the Reds opted for him to play an entire season with High-A last summer, a Triple-A promotion was only projected to be in play during the final weeks.

Since moving up to the top level of the minor leagues, Stewart has been uber productive and is making a strong case to join the Reds as they look to compete for one of the final Wild Card spots. Through his first 10 games at Triple-A, Stewart has held a .300/.300/.650 slash line with two doubles, four home runs, and a stolen base. He has only struck out six times and has scored six runs and tallied seven RBI.

However, will his impressive start at Triple-A matter for 2025 fantasy baseball?

While it seemed Stewart had a viable path to joining the majors, the Reds traded for Pittsburgh third baseman Ke'Bryan Hayes on Wednesday afternoon. While Hayes does not carry the highest upside in the batter's box, he is well-regarded as one of the top defenders at the position. In addition, young third baseman Noelvi Marte would then likely shift to another position, potentially the outfield, which could further complete the starting nine.

Matt McLain and Gavin Lux have typically held down the keystone, and neither seems to be in danger of losing at-bats. McLain started off slow but has begun to catch fire, posting a .292/.370/.415 line since July 8.

While his quick adjustment to Triple-A is very impressive, the recent acquisition of Hayes will make it difficult for Stewart to debut this season.

My personal top 10 3B prospects!

1. Sal Stewart, CIN, AAA, 21
2. Blaze Jordan, BOS, AAA, 22
3. Jacob Reimer, NYM, AA, 21
4. Brock Wilken, MIL, AA, 23
5. Cam Collier, CIN, AA, 20
6. Eric Bitonti, MIL, A+, 19 🎦
7. Kyle Karros, COL, AAA, 22
8. Tommy White, ATH, A+, 22
9.… pic.twitter.com/h2RbQe64zW

— Ross Jensen (@RossJensen12) July 29, 2025

Verdict: Continue to monitor in standard leagues

Dylan Beavers, OF, Baltimore Orioles

Orioles No. 5

After years of Gunnar Henderson, Jackson Holliday, Heston Kjerstad, and Coby Mayo making headlines after headlines in the Baltimore system, there has been a bit of fatigue in the system. While catcher Samuel Basallo has flashed immense power upside at Norfolk this season, outfielder Dylan Beavers has gone a bit under the radar.

The 23-year-old currently sits at the top 100 on MLB.com and only recently moved up to the top five in the system following several graduations.

Beavers spent the vast majority of the 2024 season at Double-A before earning a brief six-game taste of Triple-A at the end of the season. During this short look, Beavers went 5-for-20 with a double and four RBI. Through 119 games at Double-A, Beavers carried a modest .241/.343/.413 line with 19 doubles, 15 home runs, and 31 stolen bases.

However, since becoming a full-time player at Norfolk, Beavers has taken a significant step forward. Through 81 games with the Tides this season, the California product has posted an impressive .302/.412/.459 line with a .907 OPS. He has gone deep 13 times, added 13 doubles, and swiped 21 bags.

However, unlike the name above, Beavers has a viable path to join the major leagues very shortly.

At the trade deadline, the Orioles moved three outfielders (Cedric Mullins, Ramon Laureano, Ryan O'Hearn), which could open up a path for Beavers in the very near future.

Given his ability to hit for power and steal bases, he is worth stashing in all deep category formats for the time being.

Dylan Beavers is hitting .318 (!) with a .913 OPS in Triple-A this season — and he’s really starting to show some power.

After going 22 straight games without a home run, Beavers has hit seven in his past 20 games (and five in his past 10). pic.twitter.com/Q3Lr6jWcS7

— Jacob Calvin Meyer (@jcalvinmeyer) July 5, 2025

Verdict: Stash in 12+ team, five-outfielder leagues

Jonah Tong, SP, New York Mets

Mets No. 2, Overall No. 58

Rounding out this list will be a familiar name to readers of this column. Jonah Tong was featured in a previous edition during the first half, but he will earn another spot as he has yet to slow down.

The 22-year-old right-hander has looked nothing short of dominant during his tenure at Double-A Binghamton this summer. Through 89 innings of work, the No. 2-ranked prospect in the system has posted a remarkable 1.72 ERA with a sparkling 0.90 WHIP. During this stretch, Tong has struck out 128 hitters while allowing just 37 walks.

Since the start of June, Tong has held an even better 1.20 ERA with a 0.73 WHIP. Through these 45 innings of work, the budding ace has struck out an eye-catching 66 hitters while serving up just 13 total free passes.

There is no doubt that Tong is ready to join Triple-A, but unfortunately, the Mets have yet to give him the call. During the 2024 season, Tong spent most of his time with High-A Brooklyn and struggled a bit, posting a 3.71 ERA with a 1.32 WHIP.

Even though he is facing tougher competition, Tong has shown immense growth in relation to his production last season. So far at Double-A, Tong has posted a 29.3% K-BB% compared to the 19.8% he held last season at High-A. In addition, he has been able to lower his BABIP to .247 in relation to the .338 mark he held with the Cyclones.

Tong is a fast-rising pitching prospect. However, given that the Mets have kept him at Double-A, it is tough to envision an outcome where he resides in Queens. Instead, fantasy managers should expect fellow pitching prospects Nolan McLean and Brandon Sproat to debut in the second half.

Tong is a must-stash in keeper/dynasty formats, but it's best to leave on your redraft waiver wire.

Final line for Jonah Tong today for Double-A Binghamton:

3 IP, 1 H, 0 R, 5 BB, 8 K, 74 pitches/41 strikes

Lowered his ERA to 1.66, and has a minor league-leading 146 strikeouts in only 92 innings.

— Mike Mayer (@mikemayer22) July 30, 2025

Verdict: Fast-rising dynasty asset.

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