4 Impact Fantasy Baseball Prospects To Stash - Henry Bolte, A.J. Ewing, Jose Corniell, Kemp Alderman

May 15, 2026

Four top fantasy baseball prospects - Henry Bolte, A.J. Ewing, Jose Corniell, Kemp Alderman - that can make big impacts. These MLB prospects are waiver wire pickups or stashes.

Welcome to Week 7 and RotoBaller's Redraft Fantasy Baseball Prospects Report for the 2026 MLB season, looking at prospect risers and fallers in redraft fantasy baseball leagues.

As we advance deeper into the regular season, we'll take a closer look at Henry Bolte, A.J. Ewing, Jose Corniell, and Kemp Alderman. Each is a top talent in their team's farm system who has either already debuted early this season or is knocking on the door of receiving a call to the show.

We’ll dive into their early performances, analyze what’s working (and what’s not), and offer insights on what fantasy baseball managers can expect as we get deeper into the 2026 season.

Henry Bolte, OF, Athletics

Availability: 12% rostered

2026 MLB Stats: 3-for-6, 0 HR, 1 RBI, 1 BB, 1 K, 1 SB

Bolte was the Athletics' second-round pick in 2022, signing for $2 million out of Palo Alto High School. He has produced great results at the plate across all levels of the minor leagues, but he really started to take off throughout April and early May.

Bolte is known for his solid swing decisions and impressive batted ball metrics. His 76.1% zone swing rate at Triple-A ranked in the 95th percentile, while his 109.4 mph EV90 was in the 98th percentile. He had a .361 xwOBA in Las Vegas and showed off his blazing speed with 17 steals over 37 games.

We also started to see Bolte tap into more power, likely due to his increased exit velocity. He was already up to 12 homers across 37 Triple-A games this year. Through his first three minor league seasons, he posted a 2.7% home run rate. In 2026, that rate jumped more than twofold to 6.8%.

Going on a tear resulted in a favorable ouctome for Bolte. He was promoted to the majors earlier this week, and he immediately left a terrific impression. In his first MLB game, he went 2-for-2 with a steal. In total, he's 3-for-6 since the promotion. He also made a spectacular diving catch on defense.

Although Bolte hasn't yet homered in the majors, we expect the power to come sooner rather than later. Assuming that happens, his combination of power and speed will give him tremendous upside in fantasy baseball. His above-average defense should also get him in the starting lineup every day, giving him the potential to rack up more fantasy points.

On one hand, it's impressive to see Bolte already have a 12% roster share within 48 hours of his promotion. On the other hand, he should be rostered in far more leagues because of his upside and power/speed blend. Fantasy managers should strongly consider adding Bolte via the waiver wire because of his potential to have an immediate impact with rest-of-season upside.

After collecting 12 straight hits last week at Triple-A, Henry Bolte has reached in each of his first 3 @Athletics plate appearances.

And he flashes his 65-grade run tool with a 28.5 ft/sec sprint speed on this diving catch! pic.twitter.com/ECg4TBRCCV

— MLB Pipeline (@MLBPipeline) May 14, 2026

A.J. Ewing, OF, New York Mets

Availability: 24% rostered

2026 MLB Stats: 3-for-9, 1 HR, 3 RBI, 4 BB, 3 K, 1 SB

The Mets selected Ewing with the 134th overall pick in the 2023 MLB Draft. At the time, he was a top prep prospect who ultimately fetched a $675,000 signing bonus. He hit the ball quite well at every level of the minors, resulting in the Mets calling him up for his MLB debut at just 21 years old earlier this week.

The promotion was well deserved after Ewing consistently hit the ball at Triple-A. With the Syracuse affiliate, he posted a .412 xwOBA (95th percentile) and a .577 xSLG (97th percentile). His exit velocities were around average, but he did have an above-average 12.2% barrel rate.

Ewing is a reliable hitter who doesn't walk or strike out much. In fact, his 9.8% strikeout rate at Triple-A ranked in the 96th percentile. He also posted a 14.6% whiff rate and 90.48% zone contact rate with Syracuse.

There isn't a ton of power here, but Ewing makes up for it with elite speed. He stole 87 bases across 154 games in 2025 and 2026, and assuming the Mets continue to keep him active on the basepaths in the majors, his speed will allow him to rack up fantasy points.

Ewing stole a base in his debut on Tuesday, and he launched his first career home run on Thursday. The homer went 405 feet and left the bat at 110.5 mph, making it the hardest-hit ball on Thursday.

We can't say for certain that he'll continue to hit the ball at consistently high exit velocities, but there's certaingly 50-grade power potential as he reaches the majors. Plus, regardless of his power output, he'll continue to boost his fantasy value with his ability to steal bases. He's a priority waiver wire target in redraft fantasy baseball leagues.

A.J. Ewing launches his first career home run! 🚀 pic.twitter.com/8hRcuVsIs4

— MLB (@MLB) May 14, 2026

Jose Corniell, SP, Texas Rangers

Availability: 0% rostered

2026 Triple-A Stats: 2 G, 2 GS, 0-1, 8.1 IP, 2.16 ERA, 8 K, 3 BB, 1.08 WHIP, .200 AVG

Corniell originally signed with the Mariners out of the Dominican Republic in 2019, but he was traded to the Rangers in exchange for Rafael Montero one year later. He gradually developed in the Rangers' farm system, and he did make his MLB debut last season but was quickly sent down after allowing three runs over 1.2 innings in the majors.

Corniell missed the first month of the 2026 minor league season due to arm fatigue, but he has impressed in his first two outings since returning. Across 8.1 innings this year, he has an impressive 2.16 ERA with 1.08 WHIP, a .200 opponent batting average, and a .261 BABIP.

The right-hander has a solid four-pitch mix headlined by a mid-90s fastball, which he throws more than 50% of the time. It can end up being a little dead zone at times, but the results speak for themselves: his heater has a 36.8% whiff rate while holding batters to a .100 xwOBA this year.

He also throws a cutter, changeup, and sweeper. The sweeper gets good depth and misses bats, but it's been hit around over a small sample size this year. His sweeper may be his most intriguing secondary pitch; it loosely resembles a cutter, but it also has far more horizontal break than the cutter he throws. His cutter (.525 xwOBA) and sweeper (.053 xwOBA) are certainly two distinct pitches.

Corniell has been hit around a little bit this year, and although we're encouraged by his pitch mix, we'd like to see him get his ground ball rate up from 28.6%. On a positive note, he's been carried by his fastball, and he ranks in the 95th percentile with an opponent xBA of .131. He has yet to give up a barrel, he has a 33% chase rate, and he's inducing whiffs at a 40% clip.

All in all, we're still encouraged by Corniell's repertoire and results, and we're optimistic that he can be an impact starter despite last year's blemish in his MLB debut. With the injury behind him, Corniell should get a few more starts in the minors before the Rangers are ready to re-summon him to the majors. When the time comes, he'll be an intriguing, results-driven target in deeper redraft fantasy baseball leagues.

Jose Corniell strikes out Esmerlyn Valdez on an 82 mph sweeper. pic.twitter.com/bSaz1KC4JE

— Eric Cross (@EricCrossMLB) November 4, 2025

Kemp Alderman, OF, Miami Marlins

Availability: 0% rostered

2026 Triple-A Stats: 37 G, .290/.372/.486, 7 HR, 19 RBI, 5 SB, 8.3% BB%, 32.7% K%, 127 wRC+

The Marlins selected Alderman early in the second round of the 2023 MLB Draft. The Ole Miss product inked a $1.4 million signing bonus and quickly made his pro debut in the minors.

Alderman has continued to hit the ball quite well at all levels of affiliated ball. He offers an intriguing power/speed blend with 22 homers and 22 steals last year. Last year's 22 homers were a career-high, but he could eclipse that mark in 2026 since he's already at seven.

The 23-year-old has a very poor K/BB ratio, but the underlying metrics behind his contact quality are incredibly encouraging. His 109.8 mph EV90 ranks in the 99th percentile, and both his barrel rate and hard-hit rate rank among the top 5% of Triple-A batters. He's been somewhat on the aggressive side, posting a 73.1% swing rate but also whiffing and chasing more than 30% of the time.

Fortunately for fantasy baseball managers, Alderman's power/speed combo will have a much greater impact on his fantasy production than his swing decisions. We'd like to see him walk more and strike out less, but if he can be a perennial threat to accrue 20+ homers and 20+ steals, managers will be satisfied.

Now, it's time to be patient. Alderman has 57 Triple-A games under his belt, so the Marlins might give him another few weeks of developmental reps. However, if he continues to hit at such a high level, he could force Miami's hand to call him up. In the meantime, fantasy managers should rush to the waiver wire and add Alderman before their leaguemates find out and it's too late.

Kemp's old stomping grounds pic.twitter.com/g3Fs6zrmet

— Jacksonville Jumbo Shrimp (@JaxShrimp) May 13, 2026

2026 Prospect Fantasy Baseball Redraft Stash Rankings

Who are the top fantasy baseball prospects to know? Check out our latest 2026 prospect fantasy baseball rankings, which are updated regularly by Eric Cross.

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2026 Player Decisions. Looking to pick up someone else instead? Today's focus is on specific players like Henry Bolte, A.J. Ewing, Jose Corniell, and Kemp Alderman. These are some common searches for 2026 fantasy baseball waiver wire pickups.

Using The Tool. This is a simple tool but very powerful. The first step is to enter the player names that you want to compare. In the first box, search for the first player's name. In the second box, search for the second player's name. Compare up to four MLB players at once, and then click the Who To Pickup? button to see who the recommended waiver wire pickups are based on fantasy baseball rankings, projections, and more.

Improvements For Who Should I Pickup? You may have noticed, our Who Should I Pickup? tool has gotten an overhaul. We've added lots of great features for you to give you as much information as possible to win on the waiver wire in 2026. You'll see MLB player tiles with stats, projections, and a slick new interface. We hope you enjoy!

How It Works. Our RotoBaller staff puts together their weekly fantasy baseball waiver wire rankings and projections based on their research, and updates them constantly throughout the week. That information is the core data that is powering the decision-making in this tool. When you search for player names, you will only see those players who are ranked.

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Looking to pick up someone else instead? Below are some popular searches and comparisons from our Who To Pickup tool for 2026 for players like Henry Bolte, A.J. Ewing, Jose Corniell, and Kemp Alderman:

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