Five Fantasy Baseball Breakout Candidates - Upside Hitters and Pitchers On The Rise

March 14, 2025

Andy's NL hitter and pitcher fantasy baseball breakout candidates, sleepers to target in 2025 drafts. These upside players are on the rise and fantasy values.

"Breakout" is a popular term in the fantasy sports world when identifying younger players who are set to reach a new level in the upcoming season. Fantasy baseball breakout candidates are usually relatively young and have just begun to scratch the surface of their professional careers. While some have flashed elite upside at the major league level, others have yet to make their MLB debut.

The most important note about a fantasy baseball "breakout" is that this is the year to draft them at a discount. If these players live up to their potential, they can very well be drafted at the top of their respective positions next season.

In this article, I will analyze five players from the National League who are set to take their game to a new level in 2025. The ADP in this piece is from NFBC Drafts from mid-February through March. Let's dive in!

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Ivan Herrera, C, St. Louis Cardinals

ADP: 221

Ivan Herrera is set to split time at the plate with Pedro Pages, as Willson Contreras is moving to a full-time role at first base. Last season, Herrera flashed solid upside with his bat and could emerge as a strong fantasy contributor in a full-time role.

Across a career-high 72 contests, the 24-year-old posted a strong .301/.372/.428 slash line with five home runs and five stolen bases. He generated an elite .366 xwOBA and a .293 xBA, both of which were well above the average metrics.

However, the only thing stopping a Herrera breakout is his defense. Last season, Herrera placed in the 27th percentile in Pop Time. If those struggles continue, Pages could move up the depth chart into the "1A" role if Herrera's bat runs cold.

Despite this, fantasy managers in two-catcher formats should take Herrera with confidence, as he has a viable path to being a top-12 catcher simply due to his elite offensive upside. With a path to a full-time role, target him confidently before his breakout campaign.

Garrett Mitchell, OF, Milwaukee Brewers

ADP: 246

The former 20th overall pick in the 2020 MLB Draft has battled numerous injuries during the early part of his MLB career. However, he enters 2025 healthy and penciled in to serve as the everyday center field, opening the door for a breakout season.

Last summer, Mitchell appeared in a career-high 69 contests and posted a .255/.342/.469 slash line with 12 doubles, eight round-trippers, and 11 stolen bases.

Compared to 2023, Mitchell showed significant improvement against fastballs and breaking balls. In 2024, Mitchell generated a .308 xwOBA against fastballs, a nearly 60-point increase compared to the .249 xwOBA in 2023. In addition, when facing breaking balls, he lowered his whiff rate by 15 points (50.0 percent - 35.4 percent) this past season.

In addition to his progression against specific pitches, Mitchell generated an elite 75.7 mph bat speed, which was well above the average mark. In fact, only two hitters outside of Mitchell generated a bat speed of greater than 75 mph and placed in the 90th percentile. Those other hitters were Julio Rodriguez and Elly De La Cruz.

Only three hitters had a bat speed > 75 mph (min 200 swings) and a sprint speed in the 90th percentile or higher...

Elly De La Cruz
Julio Rodriguez
Garrett Mitchell pic.twitter.com/HDrWD3P5DD

— Eric Cross (@EricCrossMLB) February 10, 2025

Matt Shaw, 2B/3B/SS, Chicago Cubs

ADP: 216

Lastly, my final breakout hitter to target in the National League is Chicago Cubs infield prospect Matt Shaw. Shaw is currently expected to be the team's everyday third baseman after they traded Isaac Paredes, among others, to the Houston Astros to acquire outfielder Kyle Tucker.

Even though Shaw has yet to make his MLB debut, his production in the minor leagues suggests Shaw could be the biggest steal in drafts based on current ADP.

He opened his 2024 season by receiving his first extended look at Double-A and did not disappoint. Across 86 games, Shaw posted a strong .279/.373/.468 slash line with 14 home runs and 25 stolen bases. He then earned a promotion to Triple-A and posted an excellent .298/.395/.534 line with seven long balls and six swiped bags.

The former 13th overall pick in the 2023 MLB Draft is a rising star in the sport and could take off in the 2025 campaign. If you decide to fade the third base position, be sure to target Shaw in your drafts. He has the upside to finish within the top 10 at the position.

Ryan Walker, RP, San Francisco Giants

ADP: 106

Ryan Walker took over the closing duties in San Francisco in August and did not turn back. Since tallying his first save on August 10, Walker tossed 19 2/3 innings to the tune of a near-perfect 0.92 ERA and a 0.76 WHIP. He served up just five free passes while striking out 28 batters. He did not blow a save during this span.

Before entering the closer role, Walker was just as dominant operating as the primary setup man, logging 60 1/3 innings with a 2.24 ERA and 0.88 WHIP. He tallied 71 punchouts while earning 22 holds.

His metrics under the hood suggest that Walker could emerge as one of the sport's top closers in 2025. He placed in the 96th percentile in xERA, 94th percentile in xBA, and 98th percentile in hard-hit rate.

Walker relied on two pitches, his sinker and slider, which generated an incredible .279 and a .217 xwOBA, respectively.

Even though the Giants may not be at the top of the NL West, Walker has 30+ save upside given his incredible talent. Expect Walker to sit near the top of relief pitcher ranks after this season.

Ryan Walker should be near the top of everyone's RP rankings
Since taking over closing duties on Aug 10:
🔥 0.92 ERA | 0.76 WHIP | 28 Ks
💯 0 blown saves in 19.2 IP
Before that? Just as filthy:
⚡ 2.24 ERA | 0.88 WHIP | 22 Holds
Under-the-hood metrics 📊 scream dominance:
✅ 96th… pic.twitter.com/mD3L7yGAa0

— Andy Smith (@A_Smith_FS) March 11, 2025

Spencer Schwellenbach, SP, Atlanta Braves

ADP: 92

Spencer Schwellenbach made his MLB debut in May and steadily improved as he grew accustomed to the major leagues. Over his first 44 2/3 MLB frames, the right-hander posted a modest 4.43 ERA with a 1.16 WHIP.

However, after the Midsummer Classic, Schwellenbach was quietly one of the most dominant pitchers in the sport. Across 79 frames, Schwellenbach posted a 2.73 ERA with a stellar 0.97 WHIP. He allowed just 13 free passes (1.5 BB/9) while tallying 86 punchouts.

While his stellar command was the catalyst for his late-season success, his ability to generate groundballs also played a significant role. After July, his ground-ball rate for each of his pitches increased in August and only took a slight dip in September.

Schwellenbach leaned on his fastball in the second half, which benefited him greatly. In August, he deployed it the most (31.7 percent of the time), and this pitch generated an elite 47.6 percent ground-ball rate, the highest among his other ground-ball rates it generated during the other months of the season.

With a budding fastball and stellar command, Schwellenbach has top-15 SP upside.

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