3 Impact Fantasy Baseball Prospects To Stash - Jordan Lawlar, Marcelo Mayer, Zebby Matthews

Three top fantasy baseball prospects - Jordan Lawlar, Marcelo Mayer, Zebby Matthews - that can make big impacts. These MLB prospects are waiver wire pickups or stashes.

Fantasy managers are starting to see more prospects get called up. The Chicago Cubs have called two prospects of their own (Cade Horton and Moises Ballesteros) over the past week, and the Los Angeles Dodgers called their top prospect in catcher/outfielder Dalton Rushing ahead of their game against the Athletics on Wednesday .

That means stashing the right prospects could go a long way for your fantasy team. In this article, we will determine if fantasy managers should be stashing infielder Jordan Lawlar, shortstop Marcelo Mayer, and starting pitcher Zebby Matthews in most leagues.

So, let's dive in and see if Lawlar, Mayer, and Matthews should be stashed and grabbed off the waiver wire before it's too late.

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Jordan Lawlar, INF, Arizona Diamondbacks

Current Level: Arizona Diamondbacks
Availability: 41% rostered
2024 AAA stats: 37 G, .336/.413/.579, 6 HRs, 31 RBI, 38 R, 13 SB

It was only a matter of time until the Diamondbacks called up their top prospect. Lawlar was raking down in Triple-A to start the season, and there wasn't anything left for him to prove. He was hitting .336 with six home runs, 31 RBI, and 13 stolen bases in 37 games with the Reno Aces. The 22-year-old also tallied a hit in 17 of the past 20 games before his promotion.

Arizona eventually called him up ahead of Monday's series opener against the San Francisco Giants. However, this is the second time Lawlar has been promoted in his career. The first time came back during the 2023 season when the Diamondbacks called up the infielder to help them chase a World Series title.

Lawlar, though, didn't make much of an impact in his first taste of the big leagues. He was called up earlier in September and struggled at the plate to begin his major league career. He had just four hits across 31 at-bats (.129 batting average) to go with two walks, one stolen base, and 11 strikeouts in 14 regular season games. Despite those poor numbers, we shouldn't really read too much into that.

He was only 21 years old when he made his debut on September 7, 2023, and Lawlar has shown his potential down in the minors over the past two years. MLB Pipeline's No. 4 overall prospect batted a combined .329 with eight home runs, 51 RBI, and 19 stolen bases across 80 games between 2024 and 2025.

MLB's No. 4 prospect Jordan Lawlar in 37 AAA games this season: .336 AVG, .413 OBP, 23 XBH, 31 RBI, 13 SB, .992 OPS 🐍

What are the D-backs' plans for the 22-year-old?@jonmorosi | #MLBCentral | #Dbacks pic.twitter.com/VkHiJfr6Xj

— MLB Network (@MLBNetwork) May 13, 2025

As a result, Lawlar is worth picking up in most leagues in Week 7 of the fantasy baseball season. He has the tools to succeed in the majors and could make a solid impact throughout the 2025 campaign. This is a player who hit 20 home runs and stole 36 bases during the 2023 minor league season.

Something to keep in mind when deciding if you should pick up Lawlar is that the Diamondbacks only plan to play him four to five times a week. That means he will likely sit one to two times per week, which could be costly in weekly leagues. Still, he should be added in most fantasy leagues, given his upside in this Arizona lineup.

Marcelo Mayer, SS, Boston Red Sox

Current Level: Triple-A Worcester
Availability: 8% rostered
2024 AA stats: 77 G, .307/.370/.480, 8 HRs, 38 RBI, 60 R, 13 SB 
2024 AAA stats: 38 G, .275/.342/.500, 8 HRs, 38 RBI, 24 R, 1 SB

Fantasy managers are patiently waiting for the Boston Red Sox to call up their top prospect, Roman Anthony. However, Boston's No. 2 prospect is also knocking on the door for a potential promotion. Mayer is hitting the ball well in the minors and could be called up by the team in the coming months. MLB has his estimated time of arrival listed as 2025.

Therefore, we could expect Mayer to make his MLB debut at some point this year. The problem is that there is nowhere for him to play. Trevor Story (shortstop), Kristian Campbell (second base), and Alex Bregman (third base) are currently occupying those three spots in the infield. The prospect could transition to play first base since Triston Casas (knee) is out for the year, but the Red Sox don't seem to want to do that.

That could make it difficult for Mayer to be called up anytime soon. Nevertheless, there is a good shot that MLB Pipeline's No. 8 overall prospect makes his debut in 2025. He is currently hitting .275 with eight home runs, 38 RBI, and one stolen base in 38 games at Triple-A Worcester this season.

Marcelo Mayer came to the plate with 2 runners on and the Woo Sox down 1.

He hit his 8th homer of the year 😤 pic.twitter.com/3OOH49e1Za

— MLB (@MLB) May 14, 2025

Those numbers are definitely a positive sign for Mayer, considering he was coming off a strong campaign with Double-A Portland in 2024. He hit .307 with eight home runs, 38 RBI, and 13 stolen bases in just 77 games last year. So, there is a strong chance that the 22-year-old could make his MLB debut later this summer.

Given how the current infield looks for Boston, though, Mayer isn't necessarily a strong stash right now. It could be a while until he is called up, and even when he is promoted, he might not see frequent playing time. That means fantasy managers should just be monitoring him right now and putting him on their watch list.

Zebby Matthews, SP, Minnesota Twins

Level: Triple-A St. Paul 
Availability: 14% rostered
2024 MLB stats: 9 GS, 6.69 ERA, 1.65 WHIP, 43 K, 37 1/3 IP
2025 AAA stats: 7 GS, 1.93 ERA, 1.19 WHIP, 38 K, 32 2/3 IP

It has been fun to watch what Matthews has done in his minor league career. He finished with a 3.84 ERA and 112 strikeouts in 22 games (20 starts) at Single-A and High-A in 2023 and then had a 2.60 ERA and 114 strikeouts across 18 games (17 starts) at High-A, Double-A, and Triple-A last season.

Those two strong campaigns earned Matthews a major league promotion toward the middle of August last year. However, the right-hander really struggled in his first nine major league starts. He had a 6.69 ERA and 43 strikeouts across 37 2/3 innings while failing to pitch into the sixth inning in all nine outings.

There were surely some ups and downs for Matthews in his first stint in the big leagues. The good was that he allowed two runs or fewer in six of his nine starts and had a solid 6.2% walk rate. The bad was that he allowed at least six runs in two different outings, and opposing hitters had a 42.1% hard-hit rate against him.

Despite the inconsistencies for the 24-year-old in the majors last year, he is a solid stash candidate in most 12-plus team leagues. He has shown growth on the mound this season and has been one of the top pitchers in Triple-A in 2025. The right-hander currently owns a 1.93 ERA and 38 strikeouts across 32 2/3 innings pitched.

Zebby Matthews is too good for AAA

Get him to Minnesota now! pic.twitter.com/LEeKNVGacY

— Thomas Nestico (@TJStats) April 16, 2025

With Simeon Woods Richardson getting rocked again on Tuesday and lifting his season ERA to 5.02, the Twins could decide to call up Matthews within the next few weeks. In his most recent outing for Triple-A St. Paul on May 10, he didn't allow an earned run across 5 1/3 innings to go with four strikeouts.

So, Matthews could make a strong impact once he is promoted in 2025. He's pitching too well down in Triple-A to stay there for most of the year, meaning his time with the Twins is surely coming.

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