Hitter Fantasy Baseball Breakouts - Risers to Watch and Waiver Wire Outlooks (Week 9)

Jarod's hitter fantasy baseball breakouts, sleepers, and risers to watch for Week 9 of 2025. His list includes waiver wire outlooks and underachieving hitters so far.

Welcome back to my Fantasy Baseball Breakout Hitters article for Week 9 of the 2025 MLB season. The focus of this article is to highlight players who could be on the verge of a breakout, citing current active hitting streaks along with recent leaders in batting average and isolated power (ISO). You will also find expected batting average (xSLG) underachievers and overachievers.

In this week's edition, we'll dive into players like Jackson Holliday, Ezequiel Tovar, and Ryan Mountcastle. You'll not only find out who is hot at the plate, but also which hitters deserve better results based on their expected stats, or who might be on the verge of a cold spell.

Last week, Heliot Ramos and Carlos Narvaez were a couple of good callouts who kept on hitting. So, let's take a closer look at our breakout watch to help your fantasy baseball teams heading into Week 9. You might find a potential waiver wire target or some worthy DFS plays!

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Hit Streak Leaders

Data through 5/21

I outlined Cody Bellinger earlier this week in my Players to Watch for the Week Ahead article, so I won't rehash him here. Just know that he's still hitting well since then, now with a 15-game hit streak.

Chase Meidroth (9 games)

Chase Meidroth was called up for his MLB debut on April 11, then headed to the injured list shortly thereafter on April 21 due to right thumb inflammation. The former fourth-round draft pick hit .269 (7-for-26), but with zero extra-base hits and one stolen base in nine games.

Since returning from the IL on May 1, he's settled in, hitting .313 (21-for-67) with five extra base hits (four 2B, one HR) and seven steals in 18 games.

The 23-year-old is currently riding a nine-game hit streak that includes five multi-hit efforts, and has a stolen base in five of his last six games played.

Chase Meidroth is on FIRE 🔥 pic.twitter.com/9HBL4YuPI5

— White Sox on CHSN (@CHSN_WhiteSox) May 22, 2025

That is some unexpected fantasy goodness from a little-known player right there, and that doesn't even mention the 11 runs scored and four RBI since his return from the IL.

Can he keep it up? A superb 89.2 percent contact rate and minuscule 3.8 percent swinging-strike rate say he should continue to hit, while a 90th-percentile chase rate and 11.4 percent walk rate mean he'll keep getting on base, which should lead to more stolen bases.

With the White Sox's offensive environment, there may not be a ton of RBI opportunities, and he won't help with home runs, but he is a high average, stolen base producer, with the ability to score some runs, hitting out of the leadoff spot. His positional eligibility at 2B, 3B, and SS on Yahoo! probably warrants more than 16 percent rosters.

If he doesn't fit the profile of someone you're looking for on your season-long fantasy squad, he could be a cheap DFS option most days, with the frequent stolen bases a valuable commodity.

Jackson Holliday (8 games)

Jackson Holliday was hitting .213 on April 22 with one double, a triple, and two home runs through the first 18 games of the season. Since then, he's hit .304, and is currently riding an eight-game hit streak, but only recently did he start to pile up the hits for extra bases.

The left-handed slugger has four doubles, two triples, and six home runs on the year, but two of the doubles, one of the triples, and two of the home runs have come in the last six games alone.

Despite his initial struggles in the big leagues, we all knew the former first-overall draft pick and top-rated prospect would eventually hit, and now he's doing just that. The 21-year-old is now up to a .268/.325/.438 slash line for the year with a .335 wOBA (.351 xwOBA) and 120 wRC+.

Jackson Holliday, Last 25 games:

.302/.381/.477
.858 OPS
- 4 HR
- 9 RBI
- 8 BB
- 151 wRC+

Despite the Orioles' struggles, Holliday has been performing very well at the plate having a breakout season pic.twitter.com/ob9WIszeBk

— 𝙆am Brice (@kambrice1tv) May 20, 2025

He's still available in 35 percent of leagues and eligible at both 2B and SS, so grab him if you can, and even though the Orioles have underperformed, he could still be a viable one-off DFS play while he's hot.

Highest Batting Average Last Seven Days

Data through 5/21, minimum 13 at-bats

Ezequiel Tovar (.476 BA)

Ezequiel Tovar got off to a poor start this season, hitting .212 (14-for-66) with zero home runs and a hard-hit rate of 43.4 percent in 16 games before hitting the IL for a month.

Since returning, Tovar has been a different hitter, going 10-for-21 (.476) with two home runs (a double and a triple, too) and a hard-hit rate of 52.6 in just five games.

Ezequiel Tovar's 5th hit of the night provides a huge insurance run for the @Rockies! #RivalryWeekend pic.twitter.com/ah9U6R6t2l

— MLB (@MLB) May 18, 2025

The right-handed hitter finished as the ninth-ranked shortstop in fantasy last season. Sure, the strikeout rate was high and the walks were low, but he was still able to be a valuable fantasy commodity.

Fantasy managers must be waiting for the wheels to fall off, though. At 66 percent of Yahoo! rosters, the Venezuelan is just the 25th-most rostered shortstop.

The youngster plays half his games at Coors Field, and guess what? His contact rate thus far is 77.4 percent compared to 69.0 percent last year, and the strikeout rate has gone from 28.8 percent down to 17.2 percent.

The chase rate is still very high, but that hasn't stopped him from being very fantasy-relevant in the past, so don't shy away from him.

Highest ISO Last Seven Days

Data through 5/21, minimum 13 at-bats

Gabriel Moreno (.474 ISO)

We all know what Will Benson did last week, and the rest of the list is littered with names you would expect on an ISO leaderboard, but Gabriel Moreno is at the bottom.

Being a catcher, one might not be too surprised to see that he's only 30 percent rostered, as many teams don't need more than one backstop, but if you do need help in season-long leagues, he's likely available.

ARI - Gabriel Moreno Solo HR (3)

📏 Distance: 369 ft
💨 EV: 106.1 mph
📐 LA: 43°
⚾️ 96.9 mph four-seam fastball (LAD - LHP Tanner Scott)
🏟️ Would be out in 30/30 MLB parks

ARI (1) @ LAD (1)
🔺 9th#Dbacks pic.twitter.com/ILwYTYr1Ot

— MLB Home Runs🚀 (@MLBHRs_) May 21, 2025

If not, now's the time to be using him in DFS, as he's been hitting for extra bases as of late. Over the 25-year-old's last five games, he's gone 8-for-19 (.421) with three doubles and two home runs.

Most Steals Last Seven Days

Data through 5/21

Jose Caballero (six SBs)

Jose Caballero stole 44 bases last season, but only mustered an 83 wRC+, as he just doesn't do enough of anything else to be overly fantasy relevant (nine HRs, 44 RBI, 53 R in 139 games in '24).

In 2025, he's doing more of the same, currently with more stolen bases (15) than he has RBI (14) or runs scored (13). But six of those steals have come in the last week alone.

With the oft-injured Taylor Walls scratched with a sore groin on Wednesday, Caballero could see some increased playing time in the short term, or potentially longer term if Walls requires an IL stint.

If you're hoping to catch lightning in a bottle -- or on the basepaths -- look no further than Caballero, who is owned in just 12 percent of leagues and is eligible at 2B, 3B, SS, and OF on Yahoo!.

xSLG Underachiever

Data through 5/21  

Normally, this section is used for xBA under and overachievers, but I periodically switch it up to look at xSLG over and underachievers, and that's what I'll do this week. These guys have been hitting more (or fewer) extra-base knocks than the stats anticipate, and could soon see a change in the opposite direction.

Ryan Mountcastle (.327 vs. .448)

Like many Orioles, Ryan Mountcastle got off to an atrocious start this year, slashing .191/.240/.270 with a .229 wOBA and 45 wRC+ over his first 28 games. Since then, he's hit safely in 16 of his last 18 games.

That hot streak only translated to a .276/.291/.395 slash line with a .298 wOBA and a 93 wRC+, but it was still a major improvement.

The 28-year-old currently owns one of the largest differentials between actual SLG (.327) and expected SLG (.448), so there could be further room to run.

Perhaps some of those singles could become doubles, or some of those flyouts could become home runs, especially given his solid 11.0 percent barrel rate in 2025 with a career-high 48.0 percent hard-hit rate.

With a career BABIP of .313, one could also surmise that his current BABIP of .288 implies some bad luck. The former first-round draft pick has never finished with a wRC+ less than 108, and his current trajectory could get him back there.

At 32 percent rostership, if the 6-foot-3 slugger was dropped in your league, maybe now is the time to pick him up.

xSLG Overachiever

Data through 5/21

Geraldo Perdomo (.488 vs. .405)

Geraldo Perdomo is off to such a great start that he's on pace to blow past many of his previous career highs in RBI, steals, and more. The six home runs he's hit already match a career high mark set in 2023.

The switch-hitter can still have a fantastic season, but there are reasons to believe that the power output might not last.

Geraldo Perdomo hits the third 2-run homer of the game for the @Dbacks! 🚀 pic.twitter.com/OIppmr87WJ

— MLB (@MLB) May 20, 2025

His average EV, barrel rate, hard-hit rate, and bat speed are all 38th-percentile or worse, and despite the spike in home runs, the 25-year-old's average launch angle is lower than it was when he hit six HRs in 144 games in 2023.

Finally, throw in the whole reason he's being discussed here -- a large differential between SLG (.488) and xSLG (.405) -- and it seems like the home run pace (and extra-base hit pace in general) will slow from here.

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