Almost every season, we see young starting pitchers emerge out of relatively nowhere and produce like top-end starters for an extended period of time. This often comes after the All-Star Break when they are given an opportunity, whether that be due to injury or for teams to see what they have for the future.
Perhaps the best and most recent example of this is Spencer Schwellenbach, who mostly pitched at High-A for most of his 2024 season before getting the call. He went on to be one of the best starters in MLB after the break, holding a 2.73 ERA, 0.97 WHIP, and a 23.3% K-BB in 79 innings. The young ace was the 12th most valuable starter by fWAR in that span. We are all on the prowl for the next Schwellenbach.
In 2023, Cole Ragans broke onto the scene after being traded to Kansas City and pitched like a top 10 pitcher after the break. The year prior, Spencer Strider came into our lives and struck out nearly everyone he faced, and Cristian Javier is another example in the same season, as he pitched to a 1.60 ERA in 65.2 innings in the second half.
There are plenty of cases, and you see the point now. Let’s use some numbers and some video to see if we can project a few pitchers who could fit the bill down the stretch of 2025 and help define the fantasy season.
Zebby Matthews is currently shelved with a shoulder injury, but he has begun throwing live batting practice and should be close to beginning a rehab assignment. There’s certainly risk in putting an injured pitcher on this sort of list, but he should be back in time to pitch a meaningful number of innings for the remainder of the season. His profile is really appealing as a pitcher with a wide mix and strong command.
As a rookie in 2024, he experienced immense amounts of bad luck with a 6.69 ERA and 1.65 WHIP in 37.2 innings. But under the hood, things looked much more promising as he showed an above-average strikeout rate and walk rate with a strong 18.1% K-BB. His peripherals all signaled a better ERA in his future, with SIERA being the most bullish at 3.78. Out of 2,239 starting pitching seasons since 2015 (min. 30 innings), Matthews’ difference between his ERA and SIERA was the 27th largest. His .364 BABIP was also an outlier given his batted ball distribution and history in the minor leagues.
Pitching at Double-A for most of the 2024 season, Matthews displayed impeccable control with enticing swing-and-miss numbers. Since 2025, he has been one of seven starters with a strikeout rate north of 30% and a walk rate less than 3% at Double-A. Funnily enough, another pitcher featured here in this piece in Brandon Walter, is among the other pitchers.
Flash forward to 2025, and we see Matthews overpower Triple-A hitters to begin the season, flashing increased velocity and overall better stuff across the board, going from a 97 overall Stuff+ to 106.
The slider was what the 25-year-old was most known for as a prospect, and despite generating a good amount of whiffs (20.4% swinging-strike rate in 2024), it was tied for his worst pitch by run value with -4. He’s tweaked the shape of it a bit this year, with 1.5 inches less glove-side movement and almost two more inches of drop, leading to a small bump in swinging strike rate to 22.4% and just a .172 SLG compared to .462 last year. His 22.4% swinging-strike rate is among the top 10 highest among starters on the pitch (min. 80 pitches).
The difference may not be totally obvious when watching them, but the new version has performed much better against lefties (27.3% whiff rate in 2024 vs. 42.3% whiff rate in 2025) and maintained a similar level against righties (50% whiff rate vs. 45% whiff rate).
The 2025 season has played out pretty similarly to 2024 so far, with his ERA a tad bloated sitting at 5.21, but his peripherals all in agreement that he is doing good things. As long as he returns from his injury in a respectable amount of time with little to no restrictions, Matthews has the makings of a pitcher who could be valuable down the stretch. It’s not a bad time to stash him if he is available and you have the roster spot.
Cam Schlittler looks like the guy to get the crack at replacing Clarke Schmidt in the rotation, and his stuff looked great in his debut against Seattle on July 9. He gave up three runs in 5.1 innings, but struck out seven and reached 100 MPH on his fastball.
The right-hander mowed through multiple levels of the minor leagues this year, striking out 31.9% of the hitters he faced in 76.2 combined innings at Double-A and Triple-A. He relied heavily on his fastball and slider, throwing them more than 80% of the time in his first start. But he flashed a five-pitch mix, with a curve, sweeper, and sinker to round out his arsenal.
His big fastball is similar to Gavin Williams, with both throwing from a similar 42-degree arm angle and in the same neighborhood of movement profiles. Looking at its vertical dead zone delta, a metric on Alex Chamberlain’s pitch leaderboard site that looks at a pitch’s difference in movement over expected from the dead zone, notable pitchers that are in his range include Carlos Rodón, Spencer Strider, Spencer Schwellenbach, and Tyler Mahle.
Factor in a power slider at 91.2 MPH, and there is a lot to like with the foundation of these two pitches. There are only four other pitchers in MLB with that slider velocity or higher, which includes three relievers, and then the freshly hatched chick Jacob Misiorowski, who is a full MPH ahead of everyone.
🔥Hot Take🔥 Cam Schlittler (NYY) is a top 15 pitching prospect, and a top 100 prospect overall. Unicorn sweeper (yes it’s a sweeper), plus cut/ride fastball, and a slider/curveball pair that play off each other. Was throwing 90 in 2023, debuting today. pic.twitter.com/Wu20jUTQ0K
— Eli Ben-Porat 🇨🇦 (@EliBenPorat) July 9, 2025
He is somewhat similar to Schwellenbach last year in that he rose through multiple levels of the minor leagues before being promoted. Where they differ a bit is command, as Schwellenbach boasted a 107 Location+ as a rookie and Schlittler had a 92 in his first start. And Schwellenbach has never had a walk rate above 7.2% in the minors. But there is still a lot to like with Schlittler in that he is on a great team with exciting strikeout upside.
Brandon Walter has emerged as a critical piece of the Houston rotation, as he’s pitched to a 3.98 ERA, 1.01 WHIP, and a 23% K-BB in 40.2 innings. Maybe he doesn’t count as young since he is 28 years old, but this is his first real run as a starter in his career. Since the start of June, his 2.97 SIERA is seventh best among qualified starters. He doesn’t throw hard (91.9 MPH average fastball velocity), but distributes his five-pitch mix evenly to keep hitters off balance. The lefty throws from a funky arm slot, and he plays his sinker, sweeper, and changeup off of each other really effectively.
For the season, he owns a 5.13 Pitch Level Value (PLV), the estimated value of all pitches where 5 is league average, and Griffin Jax is the league leader at 5.56. For perspective, that is the same mark as aces Sonny Gray and Framber Valdez. On an individual pitch level, both his sinker (2.02 PLA) and cutter (2.13 PLA) rank inside the top 15 in Pitch Level Average (PLA), which looks at the value of all pitches using innings pitched and the total predicted run value of pitches thrown on an ERA scale.
As mentioned previously, he is among a cohort of pitchers with dominant strikeout and walk numbers over the last decade at Double-A. So while he is a soft tosser, he has shown an ability to miss a lot of bats previously, and it’s translated as well as you could hope to the majors this year with a 24.2% strikeout rate. He has an absurd 20/1 strikeout-to-walk ratio, with the next closest starter this season being the best pitcher in baseball, Tarik Skubal, at 10.57 (min. 40 innings). That number will obviously come down, but limiting walks somewhere close to this extent will continue to keep the floor high for Walter.
The 28-year-old’s stuff plays up due to some deception in his delivery and is somewhat reminiscent of former major league starter Alex Wood. Wood threw from an arm angle about 10 degrees lower, but they both hide the ball as they go through their delivery. Wood was a bit more exaggerated in his and brought it back behind his body more, but they feel similar in my mind.
Wood’s arsenal was never as wide as Walter’s is, which is notable and helps when the stuff isn’t overpowering. But Wood had some very solid seasons with Atlanta before becoming even better with the Dodgers. And it is greatly beneficial for Walter to be with such a progressive organization like the Astros to optimize his skill set. He should continue to rock a low WHIP while managing the home run issue that comes with a lack of velocity.
