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Marty Tallman's top pitching fantasy baseball prospects to stash for Week 21 (2026). His MLB prospects to pick up and stash on your bench and N/A spots in redraft leagues.
Welcome back to our top starting pitcher fantasy baseball prospects to stash article for Week 21 of the 2026 MLB season. Over the next week, we should see several highly touted prospects make the jump to the majors.
Now is the time to stash your favorite high-end pitching prospects who could help you down the stretch. If you have any questions, feel free to reach me on X at @Marty_Tallman.
Now, let's take a look at the top five prospects fantasy managers should be stashing for Week 21.
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Kade Anderson, Seattle Mariners
Currently at Double-A
Another week, another dominating start by Kade Anderson. Anderson is expected to be called up within the next week, and the Mariners' front office has already said he will be a starter for the rest of the season.
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 Double-A, Anderson has a 1.13 ERA, a 40.9% strikeout rate, a 38% whiff rate, a 3.8% walk rate, and a 0.65 WHIP across 87 2/3 innings. Simply put, he is the best pitcher in the minor leagues.
From an arsenal standpoint, Anderson has a 70-grade fastball that sits around 92-95 mph. It doesn't have elite velocity, but the carry through the top of the zone helps it play up.
The former LSU standout gets on hitters with a combination of carry, extension, arm speed, and pinpoint location. His slider is another strong pitch, sitting in the mid-80s with good lateral movement.
The velocity also makes it tough for hitters to sit on. His curveball is arguably his best breaking pitch. It's a high-spin, deep-breaking ball with plenty of vertical drop.
He also mixes in a changeup, which he mostly uses against right-handed hitters to keep them off balance.
Once Anderson gets called up, he'll be a must-roster in every fantasy format. He should already be stashed in all leagues, so get him while you still can.
River Ryan, Detroit Tigers
Currently at Triple-A
The Detroit Tigers acquired River Ryan in the trade that sent two-time Cy Young winner Tarik Skubal to the Los Angeles Dodgers.
Although Ryan is currently on the injured list with a hamstring strain, there's a chance he could make some starts for the Tigers down the stretch.
Much has been made about Ryan being a 27-year-old prospect, which is fair, but that doesn't tell the whole story.
The Dodgers called up Ryan in 2024, and he immediately found success, posting a 1.33 ERA, 3.84 xERA, a 22.2% strikeout rate, and a 1.18 WHIP over 20 1/3 innings.
Unfortunately, he suffered an elbow injury shortly after that and needed Tommy John surgery. Ryan missed all of 2025 while rehabbing before returning to the mound earlier this year.
Since then, he's shown flashes of the upside that made him an elite prospect while also dealing with two hamstring injuries.
In 2026, Ryan has a 4.46 ERA, 4.25 xERA, a 27.2% strikeout rate, a 5.1% walk rate, and a 1.29 WHIP across 36 1/3 innings at Triple-A. Not only can Ryan touch 100 mph with his fastball, but he also has a deep arsenal.
Rollin' on the River (Ryan)!
The @Dodgers No. 6 prospect strikes out seven in five scoreless frames for the Triple-A @OKC_Comets: pic.twitter.com/2dvOa7BcUx
— MLB Pipeline (@MLBPipeline) May 22, 2026
The slider is probably his best secondary pitch. It sits in the upper-80s with a short, sharp break and can be used both for strikes and as a putaway pitch. The curveball gives him a completely different look.
It sits around 82-85 mph with more depth than the slider and helps keep hitters from sitting on his fastball. The cutter sits in the low-90s and gives him something in between the fastball and slider.
It's another useful pitch that keeps hitters from locking in on his main two offerings. The changeup is probably his fourth-best secondary pitch right now.
It sits in the upper-80s with some sink and has flashed above-average, but he hasn't needed to rely on it much with the rest of his arsenal.
Overall, the future is very bright for Ryan, especially with the Tigers, who have proven to be a top-tier organization when it comes to developing pitching.
For this season, though, the big question is simply whether he can stay healthy. If he does, I could see him making a few starts in September as the Tigers make a final push for the playoffs.
He's worth a stash in 15-team leagues right now. Once he's healthy and in the majors, he has enough strikeout upside to be rostered in every format.
Quinn Mathews, St. Louis Cardinals
Currently at Triple-A
Quinn Mathews was pulled early from his Triple-A start on August 12, and Cardinals beat writers are speculating it could be because he's in line to start Monday's doubleheader against the Cincinnati Reds.
The Cardinals previously called up Mathews at the beginning of August, when he made one start against the Toronto Blue Jays before being sent back down to Triple-A.
In his MLB debut, he went five innings with three strikeouts and three walks while allowing six hits and two earned runs.
What impressed me most, besides his swaggy pearls, was his ability to get six of the 24 hitters he faced to 0-2.
Even with just three strikeouts, he did a good job mixing in his curveball while using his slider and changeup to generate whiffs.
As we discussed earlier this year, command has always been his biggest weakness, but he limited the damage to three walks and battled out of a bases-loaded jam.
He also did a good job limiting hard contact and keeping hitters off balance. At 22 years old and 6-foot-5, Mathews' biggest calling card has always been his ability to miss bats.
He struck out 202 hitters over 143 1/3 innings in 2024, becoming just the second minor-league pitcher since 2011 to reach 200 strikeouts in a season.
A lot of that success comes from his changeup. MLB Pipeline gives it a 60-65 grade, and it's been his best weapon for generating swings and misses while also getting weak contact.
He also throws a slider in the low-to-mid 80s, a slower curveball, and a four-seam fastball that has taken a big step forward since his college days.
Mathews sat around 91-92 mph at Stanford, but that jumped to 93-96 mph as a pro. Here's a look at his first MLB strikeout. Notice the radar gun reading.
Save that baseball!
Quinn Mathews picks up his first MLB strikeout! pic.twitter.com/NSnN4OjVW1
— St. Louis Cardinals (@Cardinals) August 1, 2026
That extra velocity gives him a little more margin for error and helps the rest of his arsenal play up.
Quinn should be back in the majors within the week and is worth stashing in 12-team formats. Once he's up, I'd pick his matchups carefully, especially against teams that struggle against lefties.
Looking at the schedule starting August 17, the Cardinals are set to take on the Reds (100 wRC+), Phillies (92 wRC+), Orioles (101 wRC+), and Pirates (88 wRC+).
Overall, it's a favorable stretch if Mathews gets called back up and sticks in the rotation.
Elmer Rodriguez, New York Yankees
Currently at Triple-A
Right-hander Elmer Rodriguez could get another shot at the Yankees' rotation, especially with Will Warren struggling over the last month.
Since July, Warren has posted a 5.40 ERA, 5.67 xERA and 1.40 WHIP over 30 innings. Rodriguez was called up in April but struggled, posting a 4.76 ERA, 5.86 xERA, 1.76 WHIP and a -1.5% K-BB%.
He's been much better since returning to Triple-A. Across 85 1/3 innings, the 22-year-old has a 2.85 ERA, 24.2% strikeout rate and 53% ground-ball rate while allowing just five home runs.
Keeping the ball in the park is especially important when you call Yankee Stadium home. Rodriguez isn't overpowering, but he does enough to keep hitters off balance.
Overall, he's more of a pitchability guy with a deep arsenal than someone who's going to rack up strikeouts with pure stuff. The best comparison for me is a young Chris Bassitt.
He mixes a sinker, four-seam fastball, sweeper, curveball, changeup, and cutter. Here's a look at his arsenal.
Rodriguez is a solid stash in 15-team leagues with a minor-league roster spot. Once he gets called back up, I wouldn't break the bank for him, but he could be a useful innings eater down the final stretch.
Ty Johnson, Tampa Bay Rays
Currently at Triple-A
The Tampa Bay Rays acquired Ty Johnson in 2024 in the trade that sent Isaac Paredes to the Chicago Cubs.
The 24-year-old righty has put together a really strong season at Triple-A Durham, posting a 3.08 ERA, 2.65 xERA, 33% strikeout rate, 10% walk rate, and a 1.04 WHIP.
Hitters are batting just .181 against him over 52 2/3 innings.
Johnson is mostly a two-pitch pitcher right now, but that's not a bad thing when both pitches are this good. His fastball sits around 91-94 mph and can touch 98, but the velocity isn't what makes it stand out.
At 6-foot-6, Johnson gets a ton of extension and throws from a low three-quarters arm slot, which makes the ball tough for hitters to pick up. That helps the fastball play above its velocity.
The slider is his best pitch. It sits around 84-86 mph and had nearly a 50% whiff rate in 2025. Johnson can throw it tighter for strikes or add more sweep and depth when he's looking for a swing and miss.
If he can develop even an average third pitch, his upside as a starter gets much more interesting.
Right now, the first-place Rays are rolling with a four-man rotation, so it wouldn't surprise me if they called up Johnson for a few starts down the stretch.
However, it's starting to look more likely that they'll use him out of the bullpen. He's pitched in relief in each of his last three appearances, going just one inning each time.
That could simply be maintenance to keep him fresh and healthy down the stretch, but I'm starting to lean toward a bullpen role.
Overall, Johnson is a solid stash in 15-team leagues. If he gets called up and lands in the rotation, he's worth a look in 12-team leagues as well, especially if you're looking for strikeout upside.
Other Prospects To Consider Stashing
- Karson Milbrandt, MIA
- Jack Wenninger, NYM
- Hunter Barco, PIT
- Brody Hopkins, TB
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