Marty's fantasy baseball prospect stashes, sleepers, and rookie waiver wire pickups for Week 9 of 2026 -- recent MLB prospect debuts and potential call-ups to monitor.
Memorial Day is often viewed as a checkpoint in baseball. By this point in the season, teams usually have a clearer sense of who they are and what their path might look like for the rest of the summer. With the expanded playoff format and additional Wild Card spots, more teams remain in contention deeper into the season than ever before. As a result, organizations are staying aggressive and making roster adjustments earlier, including calling up top prospects when veterans fail to produce.
While it was a relatively quiet week on the pitching side of the prospect world, several young hitters earned promotions to the majors. This week’s article highlights four recently called-up prospects along with one player still grinding away in Triple-A. Use this piece as a road map when looking to improve your roster with emerging young talent, but remember to find the right balance between exciting upside and reliable veteran production.
Use the RotoBaller app and this column to stay up to date on the latest prospect promotions and call-ups. This article focuses on players rostered in fewer than 60% of Yahoo! leagues. If you have questions about a specific player or comments on the article, feel free to reach out to me on X at @Marty_Tallman.
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Fantasy Baseball Hitter Prospects To Target
Max Clark, OF, Detroit Tigers (8% rostered)
Level: Triple-A
2026 Stats: 202 PA, .272/.342/.400, 31 R, 2 HR, 20 RBI, 11 SB, 9.4% BB%, 15.3% K%, 99 wRC+
The 21-33 Detroit Tigers have been one of the biggest disappointments in baseball this season. Fortunately for fantasy managers, underperformance often creates opportunity for top prospects.
Earlier this year, we discussed Tigers No. 2 prospect Max Clark, and now it may be time to revisit him as Detroit searches for an offensive spark. At Triple-A this season, Clark hasn't dominated, but he has shown an advanced approach at the plate.
Although he is not walking at an elite rate, he has lowered his strikeout rate while maintaining a .250 expected batting average or better against fastballs, sliders, changeups, and cutters. He has also shown the ability to handle fastballs up and in as well as sliders down and away.
While the power is still developing, Clark possesses a good hit tool and excellent speed. The biggest question is simply when he will be promoted, and the answer should be very soon. Over the past few weeks, Tigers outfielders have collectively posted a 68 wRC+ with just two home runs across 173 plate appearances. If Detroit does not turn things around quickly, Clark could arrive sooner rather than later.
If the Tigers fall out of contention by the trade deadline, Clark could get called up for the stretch run if Scott Harris and the front office decide to reshape the roster.
The next month will be important in determining that direction. Fantasy managers should monitor both Clark’s power numbers and Detroit’s place in the standings. They should also keep an eye on Clark’s Triple-A teammate, Max Anderson.
Anderson is another top Tigers prospect who plays second base. In 16 games with the Mud Hens, he is slashing .338/.357/.477 with two home runs and 13 RBI.
At the major league level, Gleyber Torres is still dealing with a sore oblique and has not been cleared to swing at full speed. Since Torres went down, Detroit has used Gage Workman at second base, but his 75 wRC+ suggests he is not a long-term answer, leaving the door open for Anderson.
Since there is still no clear timeline for when either Clark or Anderson could be promoted, fantasy managers are better off keeping both players on the waiver wire for now. However, they should still be monitored closely, especially in 15-team leagues.
Esmerlyn Valdez, OF, Pittsburgh Pirates (3% rostered)
Level: MLB
2026 Stats: 194 PA, .253/.381/.506, 25 R, 10 HR, 29 RBI, 0 SB, 17.0% BB%, 21.1% K%, 132 wRC+
The Pirates just recently promoted outfielder Esmerlyn Valdez, and he already has two home runs. Valdez is one of the organization’s top power-hitting prospects, and he is coming off a breakout 2025 campaign.
Across High-A and Double-A last season, he posted a .286/.376/.520 slash line with 26 home runs, 56 walks, and 130 strikeouts in 123 games. However, what truly put him on the fantasy radar was his dominant Arizona Fall League performance.
Although the AFL is no longer viewed strictly as a finishing ground for near-MLB-ready prospects, it still features plenty of high-end talent. Last season, Valdez earned AFL Offensive Player of the Year honors after slashing .368/.513/.842 with eight home runs in just 19 games.
He carried that momentum into Triple-A and found himself in the majors just 46 games later. Overall, Valdez profiles as a classic “three true outcomes” hitter: massive power, strong walk rates, and plenty of strikeouts. Here is a glimpse at his first MLB home run.
✅ First MLB Hit
✅ First MLB HR
✅ First Rookie Silent Treatment 🤣 pic.twitter.com/ynQlYOOtk4— Pittsburgh Pirates (@Pirates) May 24, 2026
For now, Valdez should be rostered in all 12-team leagues because of his power upside and his seemingly quick adjustment to major league pitching.
Jhostynxon Garcia, OF, Pittsburgh Pirates (2% rostered)
Level: MLB
2026 Stats: 103 PA, .242/.291/.463, 15 R, 6 HR, 13 RBI, 0 SB, 6.8% BB%, 27.2% K%, 92 wRC+
The Pirates also recently called up outfielder Jhostynxon Garcia. Acquired from the Boston Red Sox over the offseason, the 23-year-old corner outfielder has looked solid in limited action since arriving in Pittsburgh.
Across his first 18 plate appearances, Garcia has posted a .294/.333/.294 slash line with five singles, one walk, and five strikeouts. Although he has not homered yet, Garcia possesses legitimate 25-to-30 home run upside over a full season because of his raw power.
Earlier this year, Garcia recorded a 113.5 mph exit velocity, which would rank among the hardest-hit balls in MLB this season. To put that into perspective, he has already hit a ball harder than any ball Phillies slugger Kyle Schwarber has hit this year.
Jhostynxon Garcia's first 3 at-bats of the day for the Triple-A @indyindians:
⚫️ 107.3 mph homer
🟡 109.9 mph homer
⚫️ 113.5 mph homer@Pirates | @YoungBucsPIT pic.twitter.com/ZWG31wgE9z— MLB Pipeline (@MLBPipeline) May 12, 2026
The biggest concern with Garcia has always been his swing-and-miss tendencies, but he showed real progress at Triple-A this season. Over 194 plate appearances, he has an improved 22.1% strikeout rate along with a respectable 72.1% contact rate.
Ultimately, his long-term fantasy value will depend on whether he can consistently barrel the baseball. If he does, he has the upside to become an everyday middle-of-the-order bat rather than just a streaky power option off the waiver wire.
Playing time is another key issue, and there are a lot of question marks in the Pirates outfield. Pittsburgh currently has Oneil Cruz, Bryan Reynolds, Jake Mangum, and recently promoted Valdez all competing for outfield at-bats.
Veteran Ryan O’Hearn has also spent time in the outfield this season, but he is currently sidelined with a strained quadricep and is expected to miss at least a month.
So, who should fantasy managers roster between Garcia and Valdez? Right now, Valdez is the better short-term option because of his current production and upside. Garcia, however, has a stronger defensive profile and overall skill set, which could help him earn an everyday role over time.
For now, managers should closely monitor both players’ playing time over the next week. If Garcia shows he can stick at the major league level, he could become a viable option in 15-team leagues with five outfield spots. Until then, the safest move is to take a wait-and-see approach.
Kevin Alcantara, OF, Chicago Cubs (1% rostered)
Level: MLB
2026 Stats: 180 PA, .242/.339/.567, 27 R, 15 HR, 32 RBI, 3 SB, 12.2% BB%, 33.3% K%, 122 wRC+
Chicago Cubs outfielder Kevin Alcantara received his first big league promotion in 2024, but he has yet to establish himself as an MLB regular. With the Cubs outfield struggling, the 6-foot-6 slugger has earned another opportunity.
Alcantara possesses plus power and speed, but he has not yet been able to put everything together consistently at the plate. At Triple-A last season, Alcantara slashed .242/.339/.567 with 17 home runs and 10 stolen bases, though he also struck out nearly 30% of the time.
Not much has changed this year at Triple-A Iowa. When Alcantara makes contact, it is loud, but the problem is that he holds just a 66.1% contact rate. The biggest reason for that is his inability to hit anything other than fastballs.
Alcantara has struggled against secondary pitches, particularly sliders and other breaking balls. Even though he has shown some improvement against sliders this season, scouts still point to his long swing and inconsistent pitch recognition, which have led to him chasing outside the strike zone.
Unfortunately for Alcantara, major league pitchers will continue to exploit those weaknesses until he proves he can adjust. So what should fantasy managers expect from the 23-year-old Dominican outfielder? The honest answer is uncertainty. Conservatively, he could follow a path similar to Spencer Jones of the New York Yankees, who lasted just 27 plate appearances after striking out 44.4% of the time before being sent back down.
Or, he might be able to put together some good at-bats to earn some consistent playing time. Either way, Alcantara is worth considering in deeper 15-team leagues with five outfield spots because of the upside. Just do not overspend in FAAB or drop a proven major league contributor to acquire him. If the strikeout issues persist, he could find himself back in Iowa sooner rather than later.
Fantasy Baseball Pitcher Prospects To Target
Jonah Tong, SP, New York Mets (6% rostered)
Level: MLB
2026 Stats: 3.0 IP, 0.00 ERA, 0.33 WHIP, 22.2% K%, 11.1% BB%, 2.75 FIP
Jonah Tong is one of the most obvious prospect pickups this week after being recalled by the New York Mets. Tong pitched three scoreless innings in relief during his first appearance, allowing no runs while striking out two batters.
Although it remains unclear how long he will stay in the Mets rotation, he is currently lined up to start Wednesday against the surging Cincinnati Reds. Over the past two weeks, the Reds have held a 107 wRC+, so you may not want to start Tong in shallower leagues right off the bat.
Even so, Tong will eventually be fantasy viable because of his consistent strikeout numbers. The 22-year-old has long stood out in the minors because of his elite swing-and-miss stuff and deceptive delivery. There have even been comparisons to legendary San Francisco Giants ace Tim Lincecum.
This is the Jonah Tong x Tim Lincecum mechanics comp you're looking for. 👇 pic.twitter.com/ikuqMd6fah
— Lance Brozdowski (@LanceBroz) August 30, 2025
Unfortunately, Tong does not possess the elite velocity, explosiveness, or generational changeup that made Lincecum so dominant. With that said, Tong still features an intriguing arsenal.
His fastball has excellent shape and vertical ride, allowing it to play up in the strike zone and miss bats consistently. He complements the heater with a sharp slider and a splitter/changeup combination that gives him a legitimate weapon against right-handed hitters.
At Triple-A this season, Tong has been dominant at times, posting a 33% strikeout rate over 38 innings thanks to his strong pitch mix. The main concern, however, is his complex delivery, which has led to inconsistent command. In his first 21 2/3 MLB innings, he has also struggled with control, carrying a 10.4% walk rate. Even with the command issues, Tong’s upside makes him worth a gamble in deeper fantasy leagues.
In shallower formats, managers can safely take a wait-and-see approach and evaluate how he performs in upcoming outings, including his start against the Reds. If he delivers a strong outing on Wednesday, he should be rostered in all 12-team leagues. If he struggles, however, he may not stick in the majors for long.
More Fantasy Baseball Prospects and Rookies
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