Fantasy Baseball Prospect Risers - Rookies to Stash and Top Performers for Week 4 (2025)

Andy's fantasy baseball prospects sleepers and risers to know for Week 4 of 2025. He analyzes top MLB prospects and rookies to stash based on recent performances.

With Week 3 of the baseball season in the rearview mirror, it is time to look ahead to Week 4. We have already seen several top prospects, such as Edgar Quero of the White Sox, Zac Veen, and Chase Dollander of the Colorado Rockies, get called up to the major leagues. Fantasy managers ran to the waiver wire to grab these budding stars.

However, with almost a month of data, it is time to check in on several top prospects and see how they are performing in the minor leagues. Several top prospects have already begun to enjoy a strong start to the season. However, it is crucial to determine whether these performances truly matter in redraft leagues for 2025. Knowing which prospects to watch can put you ahead of your league mates and in the driver's seat.

Adding the right prospect can fill the missing piece on your roster and set you up for a fantasy championship. This week, we will look at two familiar names if you followed this column last season, and another budding ace in the Tampa Bay pitching factory. This fantasy baseball prospects biweekly series will examine a few key players in the minor leagues and assess whether they have a path to fantasy stardom in 2025.

• Fantasy baseball trade analyzer
• BvP matchups data (Batter vs. Pitcher)
• PvB matchups data (Pitcher vs. Batter)
• Who should I start? Fantasy baseball comparisons
• Daily MLB starting lineups
• Fantasy baseball closer depth charts
• Fantasy Baseball live scoreboard
• Fantasy baseball injury reports

Coby Mayo, 3B, Baltimore Orioles

Orioles No. 2 Prospect, Overall 13

Coby Mayo was one of the most popular stash candidates last season. Before earning the call to the major leagues in August, Mayo was producing at an elite level with Triple-A Norfolk. During the first half of the campaign, Mayo held a stellar .307/.381/.654 slash line with 16 doubles and 17 long balls.

However, during his first taste of the majors, Mayo struggled to find consistency. He appeared in just 17 games, tallied four hits (all singles), and held a 22:4 K:BB.

In spring training, Mayo also struggled to find success and was not considered for the Opening Day roster. As a result, the former Stoneman Douglas HS product was sent to Triple-A Norfolk to begin the 2025 campaign.

The former fourth-round pick has already begun to find his footing and is performing just as well as he did with the Norfolk Tide last season. Since not tallying a hit over his four contests, Mayo has posted a stellar .343/.442/.714 slash line with four doubles and three long balls in just nine contests. During this impressive stretch, Mayo has tallied seven RBI and held a strong 10:7 K:BB.

Even though the sample size is small, Mayo has taken significant strides early in the Triple-A regular season. Mayo has posted a 16.4 percent walk rate, which is six points higher than his walk rate at Triple-A last season. In addition, the slugger has also lowered his ground-ball rate by nine points, in comparison to his 2023 rate at Triple-A.

However, similar to last summer, it's hard to find a regular spot in the Baltimore lineup for Mayo. Currently, Jordan Westburg spends most of the time at the hot corner while top prospect Jackson Holliday covers the keystone.

While Holliday has shown growing pains (one hit over his last six games entering Friday) and could open a spot for Mayo, the team will likely continue to give Holliday time to work out his struggles.

In addition, Ramon Urias and Jorge Mateo have been trusted utility infielders in Baltimore as well.

As a result, while Mayo carries high upside, he should only be stashed in deeper formats for now.

Coby Mayo is heating up...#Birdland pic.twitter.com/xQZG5THOLn

— Eric Cross (@EricCrossMLB) April 16, 2025

Verdict: Stash in 15-team leagues

Moises Ballesteros, C, Chicago Cubs

Cubs No. 4 Prospect, Overall 66

The Chicago Cubs have several budding hitters in their system, including Matt Shaw, Kevin Alcantara, and Owen Caissie, which often causes backstop Moises Ballesteros to be overlooked. However, the young catcher has enjoyed an impressive start to the season and has caught the eye of several fantasy managers.

Through the first 14 games of the Triple-A regular season, Ballesteros has posted stellar .379/.419/.586 slash line with four doubles, one triple, and two long balls. He has tallied six RBI, scored 10 runs, and held a 9:4 K:BB.

The 21-year-old spent his 2024 campaign split between Double-A and his first taste of Triple-A. In 56 games with Double-A Mississippi, Ballesteros slashed an impressive .299/.372/.495 line. Then, during his first look at Triple-A, the catcher continued to swing a hot bat, holding a .281/.340/.454 line with 15 doubles and 10 long balls.

It is very promising to see Ballesteros continue his steady play at Triple-A during the early part of the 2025 season. In addition, during the first two weeks of the season, Ballesteros is even showing a better eye at the plate, as he is striking out at a 14.5 percent rate, a stark decrease from the 21.2 percent rate he held at Triple-A Iowa last summer.

Does this production truly matter for 2025? Unfortunately for Ballesteros, the Cubs have been one of the NL's top offenses at the start of the campaign. Much of their production has come from behind the dish as veteran backstop Carson Kelly has gone deep four times in his first nine games.

While Miguel Amaya and Kelly will continue to share the opportunities, Ballesteros will only be in contention to earn the call until one of them misses time with an injury.

Moises Ballesteros hit 2 home runs last night! His projections, no regression:

.293 ba
.353 obp
.492 slg
23 hr
86 rbi
9% bb%
17% k%

Is he the top catching prospect in baseball?

pic.twitter.com/VmtM0rECsU

— Scout the Statline (@StatlineScout) April 17, 2025

Verdict: Continue To Monitor, On Track For 2025 Debut

Ian Seymour, SP, Tampa Bay Rays

Rays No. 20 Prospect

The final prospect I want to highlight is left-handed pitcher Ian Seymour of the Tampa Bay Rays. Seymour has enjoyed an impressive start to the Triple-A regular season. Across 20 innings (four starts), the southpaw has held an impressive 2.70 ERA with a 1.15 WHIP. He has shown elite control, holding a near-perfect 26:3 K:BB.

He has averaged at least one strikeout per inning in three of his four starts. Last summer, the No. 20-ranked prospect in the Tampa Bay system began the campaign with Double-A Montgomery before seeing his first look at Triple-A Durham.

In 91 1/3 innings with Double-A, the left-hander struck out 99 batters and posted a 2.36 ERA with a 0.83 WHIP. Then, during his first taste of Triple-A ball, the left-hander continued to impress, as he posted a 2.33 ERA with a 1.15 WHIP across 54 frames.

During this stint, he struck out 63 batters. This is a great sign to see Seymour continue to flash elite strikeout upside while still showing strong command of his pitches.

A look under the hood shows that Seymour has taken significant strides forward during the early part of the campaign. In the early part of 2025, Seymour has held a 3.94 FIP with a 31.7 percent strikeout rate, which were both improvements compared to the 4.25 FIP and 27.9 percent strikeout rate he held during his first taste of Triple-A in 2024.

The Virginia Tech product could be much closer to his MLB debut than many believe. The 26-year-old is currently on the 40-man roster and could be promoted to the major leagues fairly easily without needing to remove anyone from their current 40-man roster. He may only need another handful of starts to take the struggling Zack Littell's spot in the rotation (5.48 ERA, 1.26 WHIP).

Ian Seymour matches his career-high with 🔟 strikeouts tonight!

Final line: 5.0 IP, 3 H, 1 R, 0 BB, 10 SO pic.twitter.com/uTS8dFy4fj

— Durham Bulls (@DurhamBulls) April 3, 2025

Verdict: Stash in 15-team formats

More Fantasy Baseball Prospects and Rookies