Fantasy Baseball Prospect Risers - Rookies to Stash and Top Performers for Week 20

August 9, 2026

Jeremy's top fantasy baseball prospect risers, breakouts with big upside for Week 20 of 2026. He analyzes top MLB rookies and call-ups to stash who are surging.

Welcome to the Week 20 edition of the top prospect performers. In this weekly piece, we take a look at some of the top-performing minor leaguers who could matter in fantasy down the road. While some may be promoted more quickly than others, it's important to stay up to date on recent prospect performances so you're ready to add them when they do get the call.

The most notable recent prospect promotion was Kaelen Culpepper, who has been featured in this piece multiple times this season. He enjoyed a memorable major league debut, homering in his second big league at-bat. He's worth adding in any league where you need middle infield help, and there may be many more prospects getting the call soon, too.

The important rule to note is that if a player doesn't gain more than 45 days of service time by the end of the season, they retain their rookie eligibility for 2027. That means that come August 14th, teams can freely call up their top guys and still earn possible rookie of the year incentives next season. With this being the last edition of this piece before that date, now is a good time to highlight three familiar names who could immediately earn a promotion when that time comes.

Kade Anderson, SP, Seattle Mariners

Mariners No. 1, Overall No. 5

The biggest news regarding Kade Anderson isn’t actually about him personally, but it’s that the Mariners shipped Luis Castillo to the White Sox at the trade deadline. That freed up some space in their already log-jammed rotation, so now they’re back to five capable major league starters instead of six. 

That makes Anderson the next man up if an injury occurs, or if they decide to go to a six-man rotation or piggybacking situation once again to preserve their starters’ arms. No matter what ends up happening, we don’t have to worry about Seattle placing the rookie in the bullpen down the stretch, as Jerry Dipoto, the president of baseball operations, clarified that he will serve as a starter once they do decide to call him up. 

In terms of his performance, it’s been business as usual for the lefty, who most recently struck out nine over 5 ⅓ scoreless innings against the Amarillo Sod Poodles. It was his third consecutive scoreless outing, and this streak has just added to his already spectacular year. 

Kade Anderson was awesome again. Final line: 5.1IP, 3H, 0R, 0BB, 9K, 19 whiffs, 78 pitches, 58 strikes.

12th start without allowing a run.

Anderson in his first professional season:
17G, 1.13ERA, 87.2IP, 45H, 12BB, 128K. pic.twitter.com/YshHD76jle

— Mariners Minors (@MiLBMariners) August 8, 2026

In 87 ⅔ innings at Double-A, the phenom has posted a 1.13 ERA and 0.65 WHIP with 128 strikeouts and 12 walks. Those are numbers you'd expect to see in a video game, as that's about as dominant a season a pitcher could have at any level. The 22-year-old already has the stuff to be a frontline major league pitcher in his first professional season, featuring a four-pitch arsenal that is polished from all angles. 

Fantasy managers have been waiting months for the youngster to finally get the call, and it may finally be on the horizon. Of course, the caveat is that you won't end up getting a ton of starts out of him for your fantasy team by the time he's called up, but he'll be a must-add nonetheless. Especially in head-to-head leagues where playoffs determine your league's champion, he could be a league winner.

Verdict: Stash in 10+ team leagues

Joshua Baez, OF, St. Louis Cardinals

Cardinals No. 3, Overall No. 44

Joshua Baez has been on the brink of a promotion for a while now, ever since his four-homer game in mid-June. He's gotten hot and cold many times this season, and the cold spells were enough to make the Cardinals hesitate up until this point. That could change soon once the August 14th deadline hits, and St. Louis trading away Lars Nootbaar at the trade deadline might have been the first hint.

That leaves a platoon of Bryan Torres and Everson Pereira in left field, which is not a situation a major league team should find themselves in for very long, especially when they have a much better option waiting in Triple-A. Baez most recently homered on Friday, and he's recorded at least one hit in seven of eight games in August.

For the season, the 23-year-old is slashing .252/.324/.572 with 33 home runs, 87 RBI, 76 runs, and 18 stolen bases in 100 games. He has elite raw power, posting a 115.4 mph max exit velocity, a 51.9% hard-hit rate, and a 20.1% barrel rate, which all rank among the league's best in Triple-A.

Joshua Báez extends his Triple-A HR lead with a 112.7 MPH ROCKET 🚀

The @Cardinals' No. 3 prospect tallies his 33rd long ball of the season for the @memphisredbirds: pic.twitter.com/glOPfoOiVV

— MLB Pipeline (@MLBPipeline) August 8, 2026

That doesn't mean he doesn't have his downsides, too, such as a 29.3% strikeout rate and 8.1% walk rate that both stand out as poor for the level. If those both get even worse in the big leagues, the youngster could have serious problems with consistency and batting average. However, people had that concern about Bryce Eldridge, too, and so far he's struck out three percent less in the majors.

If Baez follows a similar path, he could immediately ascend to must-start status for fantasy. Especially with less than two months left in the year, consistency starts to matter less and less. It's all about finding the hot streaks to ride to maximize as many stats as possible, and he definitely has the upside to carry your team over the final stretch of the year if he gets promoted and starts out hot.

Verdict: Stash in 14+ team leagues

Walker Jenkins, OF, Minnesota Twins

Twins No. 1, Overall No. 14

Walker Jenkins has remained hot in Triple-A, most recently going 2-for-5 with a triple and a walk on Saturday. That follows a two-homer game this past Thursday, and he's now batting .357 in the month of August through six games, which could give the Twins a chance to promote him if they're looking to choose a time when he's hot.

For the season, the outfielder is slashing an excellent .299/.388/.500 with eight home runs, 20 RBI, 45 runs, and 11 stolen bases in 61 games. He missed over a month and a half with a shoulder sprain but didn't let that slow him down, as his 162-game pace would be 21 home runs and 29 steals, which is a very nice power and speed combo.

108.2 mph | 400 ft 👀

MLB's No. 14 prospect Walker Jenkins collects the first multihomer game of his career!@Twins | @StPaulSaints | @TwinsPlayerDev pic.twitter.com/6c2fu4vVu7

— MLB Pipeline (@MLBPipeline) August 7, 2026

The 21-year-old does most things well, with a 90.8 mph average exit velocity that ranks in the 84th percentile, a 15.7% strikeout rate that ranks in the 83rd percentile, and great speed that places him in the 84th percentile. This is a great all-around profile that hasn't just come out of nowhere, as the prospect has consistently shown this upside ever since beginning his professional career in 2023.

Jenkins has dealt with a wide array of injuries over the years that have always kept him from playing full seasons to deliver truly eye-popping totals, but with a .296 career batting average through 253 minor league games, there has never been a moment where he's looked overmatched.

That's why the end of 2026 would be a perfect opportunity for the Twins to give Jenkins a chance to face major league pitching while he's healthy, with the hope of him being an everyday contributor right away at the start of 2027. They already just called up Culpepper, so Jenkins could be next.

With players such as Alan Roden, Austin Martin, and Ryan Kreidler consistently seeing work in the outfield, there's clearly not a huge buildup of talent that is blocking his path, so it's only a matter of time before they give him a chance. He could be a franchise piece that Minnesota builds around in the coming years, and you'll want to add him in fantasy once he gets the call.

Verdict: Monitor for promotion

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