13 Most Improved and Lightly Rostered Pitching Prospects
13 Most Improved and Lightly Rostered Pitching Prospects
Nate Handy of B-Sides Prospects breaks down 13 pitching prospects who have made big leaps forward in 2024.
By: Nate Handy
Who might be making legit developmental gains and still lightly rostered? That was the question when subtracting last season’s numbers from this year’s for over 650 pitching prospects with a minimum of 30 IP from each season. BB%, K%, WHIP, xFIP, GB%, SWStrk%, and Strk% were the main divining rods looked at, with K-BB%, ERA, LD%, and FB% supplementally added. Green is better than red on the color scales here and they may be dated by one outing at this juncture.
Of course there were some bigger names like Tink Hence, Zebby Matthews, and others who have gotten the dynasty owner’s love, either this season or already invested. But the following are some arms still rostered less than 2% on Fantrax, whereupon the eyeballs and numbers are pointing to substantial gains made or in the making. Sure the sample sizes might be small, but at the least, we can say these aren’t bad signs.
Arms who have improved in a good chunk of these categories (and even less so while jumping up a level) are outliers. Of the 650ish arms, only three dozen or so have as numerous and substantial jumps as the following arms. Furthermore, some of those “improvements” were more about how poorly things went last season. Mudding through it all, here are the most interesting names, some I have history with, some I’ve only recently begun learning about. I’ll roughly list them from most to least dynasty appeal for me as things sit today:
LHP Spencer Giesting D’Backs 2%
22 yo, 6’4”, A+ 2024
318th overall pick 2022 Draft - UNC-Charolette
Flip on a Giesting start in Hillsboro and you’ll get plenty of the booth remarking on how much he’s improved. Giesting’s a tough video watch in a small league with no halfway decent angles to watch a lefty, but it’s easy to glean his newfound efficiency. So be it the same level of competition as last season, the young lefty has taken a leap. The better execution of the four-pitch arsenal, particularly his breaking ball, has led to better strike throwing and flipped 7% of his 2023 walks into strikeouts. The former early second day selection is asserting himself as a serious prospect in the system, as he’s been dominating the NWL.
https://x.com/pitchingspecs/status/1793530418895143281
RHP Yujanyer Herrera Brewers 0%
20 yo, 6’3”, A+ 2024
International FA 2019 - Venezuela
We got into Herrera some a little ways back: Episode 30 of Prospect B-Side Podcast. Herrera’s been logging more innings per outing, going six his last time out (6/1) while allowing just one hit (a solo home run). Walks have been a big improvement this season, but showed themselves, giving up five that day. Herrera’s propensity to pitch backwards, not relying too heavily on his hard four-seamer, and improved execution has made him a buzzy name in the system. Strikeout stuff isn’t strikeout stuff until it’s used well and Herrera’s a big arrow up in this regard. A plus 20some K-BB% this season is wild.
https://x.com/pitchingspecs/status/1786251662430027987
RHP Dylan Cumming Giants 0%
25 yo, 6’4”, AA 2024
Undrafted FA 2022 Draft - Independent Ball via Liberty
A 17% increase in strikeouts is absurd. A little tick down in walks is nice but it doesn’t appear more strike-throwing/better execution accounts for such a giant jump. Cumming does seem to be executing his best pitch (slider) better than last season, but one wonders if there’s a new and improved tool in the attack making this all play better. On the surface, Cumming might scream potential reliever, but if you define a starting pitcher by how well he executes his best pitch, Cumming may fit the bill and why the Giants seem to be letting him piggyback and start. Cumming is intense, but how intense will his slow sideways hook be for the best hitters in the world? Here’s a look at his whiffs and called third strikes from his recent double-A debut.
RHP Trevor Martin Rays 1%
23 yo, 6’5”, A+ 2024
104th pick 2022 Draft - Oklahoma St.
Martin’s gains aren’t as gaudy-looking as others here, but considering the looks taken in of the improved execution of the entire arsenal, Martin’s impressing. Showing an ability to fill up the zone with all his offerings, efficiently racking up strikeouts, and getting whiff on all his pitches (below), the former third round pick may be putting it together, looking like a more polished sum of all the parts arm with strikeout game. Here’s his 11 strikeout pitches from 5/3:
RHP Austin Peterson Guardians 1%
24 yo, 6’6”, A+ 2024
271st pick 2022 Draft - UConn
They say Peterson’s stuff has taken a jump, which checks out as he’s made gains across this board. Sure Peterson is a bit older for high A, but this is still just his second pro season and a shot in the uppers seems close. Peterson is showing out as a supreme strike thrower, pounding the zone with his full starter’s kit. Yet, wondering if the attack will need more sophistication feels fair. Here’s a good angle of the strikes earned during two strikeouts (4/24), illustrating his propensity to live in the middle third, a dangerous proposition against elite hitters:
RHP Joseph Montalvo Rangers 1%
22 yo, 6’2”, A+ 2024
584th pick 2021 Draft - FL prep
No magic new pitch, no big velocity gains here, just a young talent proving himself as he’s moved up a level in competition. Montalvo’s showing an ability to execute at a requisite level, while the arsenal flashes enough teeth to miss bats and get chase. Here’s a look at a couple strikeouts from the best angle to see him so far this year:
RHP Eiberson Castellano Phillies 0%
23 yo, 6’3”, A+ 2024
International FA 2018 - Venezuela
It’s been a bit of a slow burn for the young Venezuelan, who’s teetered between relieving and starting during his pro career. Castellano repeated A-ball in 2023, fairing more poorly than he had in 2022. Despite this, the video has impressed this season, even before his latest outing (13 Ks vs Brooklyn). Castellano’s velocity is above average, sitting mid-90s, but he’s showing out as a spin maestro, buckling knees and getting folks to flinch at a few different breakers. Unsure what the story was in 2023, Castellano is starting to stack impressive game logs and one to watch.
RHP Jacob Steinmetz D’Backs 0%
20 yo, 6’6”, A 2024
77th pick 2021 Draft - NY prep
Steinmetz had a highly coveted frame and lively arm out of the 2021 prep class, but, classically, needed refinement. It seems it may be coming along. The numbers above don’t include, arguably, his best pro start from 5/30. Here are the nine strikeout pitches from that outing, highlighting a nice feel for spin. Steinmetz is just better than the last time you saw him…like every time:
RHP Garrett Burhenn Tigers 0%
24 yo, 6’4”, AA 2024
255th pick 2021 Draft - Ohio St.
Burhenn’s stuff just looks nastier than last year, and the numbers back it up. The newfound swing and miss/strikeout game seems to have followed him to the uppers as well, at least his first three outings. Burhenn’s offerings seem to complement each other well, with three offerings in the three velocity bands and ability to execute them. Add another good looking arm to the Tigers rich stable. Here’s a look at a few strikeouts from a good angle:
RHP Robinson Pina Phillies 0%
25 yo, 6’5”, AAA 2023 (currently in AA)
International FA 2017 (Angels) - D.R.
Over the last several seasons, mostly while in the Angels’ lower levels, Pina had some very impressive showings. Liable to pop a gaudy looking line from time to time, the consistency just didn’t seem to be there. “Is this a guy?” Still unsure how to answer that, there’s more confidence in saying Pina is the best he’s ever been, right now, repeating double-A, but with a different organization. The aggressive Angels gave Pina two stints of triple-A run last season, but it didn’t go well. Here’s a look at some Statcast stuff from Pina’s last outing as an Angels prospect:
2024 Pina looks like a different story though. Here’s a look at Pina a calendar year ago with high-A Tri City, followed by a look at his 4/23/24 outing with Reading:
The fastball is different, seeming to have more armside run. The arm slot is different. Pina’s execution of the fastball has looked better as well. The production is better too. But before you go throwing shade on the Angels pitching development and praising the Phillies for some potential good work here, these evolutions were in motion last season. Here’s a look from the end of his 2023 with Salt Lake City:
Pina might be one to watch the rest of this season to see if these gains stick and a third trip to triple-A is the charm.
LHP Walter Pennington Royals 0%
26 yo, 6’2”, AAA 2024
Undrafted FA 2020 Draft - Colorado School of Mines
Pennington has been ridiculous, earning a K-BB% jump only the likes of Dylan Cumming competes with. The soft-tossing lefty had the slider, but the introduction of a cutter for right hand hitters has seen his effectiveness sky rocket:
Everything feels like a potential multi-inning reliever here, as the Royals have recently upped his pitch count and innings. The dynasty appeal is highly questionable. But when/if such an arm keeps finding success in such a role, they tend to turn into starters. Betting that happens here? No. Curious if there’s a sliver of a chance? You bet.
RHP Aaron Davenport Guardians 0%
22 yo, 6’, AA 2024
186th pick 2021 Draft - Hawaii
Davenport was a personal favorite deeper FYPD speculation in 2021. It hasn’t gone as hoped, but 2023 Davenport has a different feel; more controlled intensity than before…and better execution. Davenport’s improved as he’s jumped to the uppers, and the numbers show it. Are we sounding the dynasty alarm? No, just noting there’s an unusual jump in production going on here from a seemingly different man on the bump. Davenport’s always had a good spin game, as the following shows. The whole arsenal is tighter this season:
(1-CHG Hunter Bishop L, 2-SLD Andy Thomas L, 3-SLD Christian Koss R, 4-CRV Jimmy Glowenke R, 5-CRV Logan Wyatt L, 6-CRV Grant McCray L)
RHP Juan Daniel Encarnacion Red Sox 0%
23 yo, 6’2”, A+ 2024
International FA 2018 - D.R.
Late 2022 gleaned a young lively arm who might have the athleticism, showing signs of harnessing it all. At least that was the thought when Encarnacion was an official B-Side selection heading into 2023. The consistency didn’t come. But has it now? Unsure if there seems to be a change in arsenal going on, nor some huge jump in execution. There’s more to be learned here, but we can’t deny encouraging signs. Encarnacion isn’t sounding the dynasty alarm just yet, but he’s put himself back on the watchlist in 2024. Here’s him striking out the very good Charles McAdoo:
