The meteoric ascent of Quinn Mathews is one of the most unexpected in recent memory. Mathews went from a good prospect with limited upside to one of the top pitchers in the Minor Leagues in just five months’ time. As we enter the offseason, I took a deep dive at Quinn Mathews to see what makes the Cardinals’ #2 prospect so good.
Who is Quinn Mathews?
Mathews is a California kid who was born in Mission Viejo before playing his prep ball at Aliso Niguel HS. He was a Top 100 player in the state coming out of high school but never gained national recognition. Mathews joined the Stanford baseball program in 2020 and had minimal success his first two seasons in Palo Alto before breaking out in 2022. As a junior in 2022, he recorded nine wins and nine saves with a 3.08 ERA, striking out 111 batters in 99 1/3 innings. His performance led him to be a two-time National Pitcher of the Week and Honorable Mention All Pac-12. The Rays drafted Mathews in the 19th round, but the left-hander returned to Stanford for his senior season.
As a senior, he became a star as the team’s Friday night starter, a designation reserved for the ace of the staff. Mathews finished his final season with 158 strikeouts in 124 2/3 innings and posted 10+ strikeouts in eight starts. His shining moment was a 16-strikeout, 156-pitch performance against Texas in the Super Regional, propelling the Cardinals to the College World Series. Mathews was First Team All-Pac 12, Pac-12 Pitcher of the Year, a First Team All-American, and a semifinalist for the Golden Spikes Award. In his Stanford career, Mathews won 25 games, converted nine saves, and recorded 343 strikeouts in 311 2/3 innings. The St. Louis Cardinals made Mathews a 4th-round in the 2023 Draft. After an extended collegiate season, Mathews did not appear in any Minor League games following the Draft.
Physical Traits and Delivery
Standing at 6-foot-5 and weighing 210 lbs, the 23-year-old left-hander is a more physical version of Chris Sale. Mathews entered the Cardinals system at 185 lbs but improved his physique following the Draft. According to Baseball America, Mathews went to work at the Cardinals’ complex with a focus on adding weight. His workout regime yielded 20+ pounds of muscle. By doing so, Mathews gained substantial velocity gains while also pitching deeper into games. Mission accomplished!
Mathews’ wind-up and delivery are very influential in his success. He starts his wind-up on the right side of the rubber with his feet spread apart. Mathews rocks back and briefly hesitates before lifting his hands over his head. During his delivery, Mathews drops the hands to his waist, separates his hands, and drives toward the plate. His body torques enough to hide the ball, which helps his arsenal play up even more.
Arsenal
It was important to highlight the physical gains that Mathews experienced in the offseason before the 2024 season. Despite his collegiate success, Mathews was projected as a swing reliever or, in a best-case scenario, a back-end rotation type. The added physicality had two effects: the ability to consistently pitch deep into games and, most importantly, a substantial velocity increase.
Four-seam Fastball: His fastball was the biggest benefactor of the velocity gains. The pitch sat around 91mph at Stanford with a max of 94. In 2024, he averaged 94.4 mph and topped out at 97. Mathews’ combination of a low vertical approach angle (under 6ft) and high induced vertical break (17.9 in) attacks hitters up in the zone.
Changeup: Mathews’ changeup is the most devastating pitch in his arsenal and features an average of nearly 11 inches of arm-side run. Opposing hitters had a 48.6% strikeout rate and 55.4% whiff rate on the changeup, making it the most successful pitch in his arsenal. The changeup is particularly effective against right-handed hitters. In 32 measured at-bats against righties, it generated 36 whiffs and was responsible for 17 strikeouts (53.1% K-rate).
Curve: A mid-70s curveball sets the tone for the breaking pitches. It has a nice arc with an average of eight inches of vertical drop paired with ten inches of run to the glove side. Mathews is comfortable throwing the curve in any count and in any quadrant of the strike zone. Most hitters do one of two things with his curveball: hit it on the ground or swing right through it.
Slider: The slider, which now sits in the mid-80s, improved by four miles per hour versus his collegiate days. The key element is the deception of the pitch, which comes from the same tunnel as the fastball and has made hitters look silly. Even though the slider lacks significant movement, it offers enough of a wrinkle to keep hitters off-balance. Mathews has had decent success with the slider, but it’s quite a luxury to have your fourth-best option generate a 50% whiff rate.
Measured Results
Historic 2024 Season
Mathews’ 2024 journey began by manhandling hitters at Low-A Palm Beach. Mathews accumulated 52 strikeouts in 30 2/3 innings, including an 11-strikeout performance in his second career start and 13 K’s in his fourth. He was quickly promoted to High-A, where he experienced similar success. Mathews struck out six or more hitters in all of his starts at the level, posting a 2.68 ERA and holding hitters to a .157 average against. In total, Mathews had a 2.18 ERA with 110 strikeouts against 20 walks in A-ball.
With Mathews firmly on the prospect radar, he took his game to the next level while pitching in the hitter-friendly Texas League. He made nine starts for Double-A Springfield. In those starts, he had a 2.41 ERA with 70 strikeouts and 15 walks over 52 1/3 innings. For context, among qualified pitchers, only two had an ERA under 3, and just three posted an ERA under 4. Hitters had a measly .186 AVG, a .277 SLG, and a .534 OPS against Mathews. Most of the damage came early in Double-A, as he allowed 11 earned runs over 20 2/3 innings. Mathews settled in after that and was completely dominant. The most impressive run of his season was a five-start stretch from July 31st to August 23rd. Mathews allowed just five earned runs and 15 hits across 31 2/3 innings while striking out 49 hitters compared to eight walks. Having accomplished all he could at the level, the Cardinals promoted Mathews to his final stop at Triple-A Memphis.
His Triple-A results were less favorable. The staple of Mathews’ dominance in the lower levels was his command and ability to pound the strike zone. While adjusting to a new level and the presence of the ABS system, Mathews struggled to throw strikes. In four starts spanning 16 2/3 innings, he walked 14 hitters, exactly one less than he walked in nine Double-A outings. Overall, he managed to throw just 57% of his pitches for strikes in AAA, compared to 65% at the other levels. Putting men on base proved detrimental. The combination of walks and timely hitting ballooned his Triple-A ERA to 6.48. Hitters fared well, batting .277 with a .438 SLG and .848 OPS. But looking at the underlying data, Mathews still managed to suppress hard contact, yielding an 86.8 mph average EV. He allowed 13 hard-hit balls in his four starts, with most coming against his fastball.
He had a 2.76 ERA and 0.98 WHIP in 26 starts, striking out 202 hitters against 49 walks. In doing so, Mathews became the 2nd pitcher in the past 13 seasons to do that, joining Brandon Pfaadt, who accomplished the feat in 2022 (218 K). Mathews was named Baseball America’s Minor League Pitcher of the Year and the MiLB Pitching Prospect of the Year. He has become the #2 prospect in the Cardinals organization and a consensus Top 50 prospect in baseball.
QUINN-SANITY 😮
Final line for Quinn Mathews tonight: 7.0 IP, 5 H, 0 R, 0 BB, 11 K.
Minor League Baseball's strikeout leader now has 168 Ks on the year. pic.twitter.com/xY8Jg7l6SO
— Springfield Cardinals (@Sgf_Cardinals) August 18, 2024
Fantasy Outlook
The hardest part about evaluating prospects is assigning value to them in the fantasy realm. As a real-world pitcher, Mathews has taken incredible strides to improve his repertoire and become a front-of-the-rotation arm. With a true four-pitch mix, he can keep hitters guessing from at-bat to at-bat and expose hitters who sell out on one particular pitch. His mechanics are simple, consistent, and repeatable. With deception in his delivery and a high-powered arsenal, hitters get very uncomfortable in the box. Mathews also improved his command since making his pro debut, and if you take out his Triple-A hiccup, he would have posted a walk-rate of around 7%.
So, how does this translate to fantasy? We know Mathews will miss bats at a high rate, giving him above-average strikeout potential. His command will limit free passes, and his pitch mix should suppress hard contact. When there is hard contact, Mathews limits fly balls, which should help with run prevention. But any pitcher who allows higher groundball and line drive rates runs the risk of a higher BABIP, which could slightly inflate his ratios. My projection for Mathews is an ERA in the mid-to-upper 3’s with a WHIP around 1.10. Mathews’ win potential is enhanced by his ability to pitch deep into games, and he should rack up plenty of quality starts. His ceiling as a fantasy starting pitcher is a Top 25 arm, although his floor feels much higher and safer than the current high-level pitching prospects.
Conclusion
The rise of Quinn Mathews has been quite a ride. Mathews started at Stanford as a swingman in his first two seasons before moving into a hybrid role as a junior and becoming the staff ace as a senior. His hard work and dedication to his body are admirable and have paid off with career-altering velocity gains and improved stamina. Mathews will make his MLB debut in 2025, whether it be out of camp as the Cardinals’ fifth starter or as a mid-season call-up. If you have a chance to add him in your dynasty leagues, I’d absolutely make the deal happen. Mathews will be an innings-eater with outstanding ratios and provide much-needed stability to any rotation. Don’t expect a megastar, but Mathews has the talent to anchor a rotation in the big leagues for years to come.
Interesting read, thanks! I’m a fan of Quinn Mathews, I think he’s really intriguing. Based on the eye test alone, he seems to both (a) fill the strikezone and (b) get a lot of in-zone swings-and-misses, which would portend well for his projected ceiling. I also think his pitching mechanics are strong and effectively utilize the kinetic chain to efficiently generate force/velocity with the entire body.
I do wonder, however, just how well his performance level with transfer to the big league level. That’s probably due in part to his meteoric rise, which substantially outperformed where he was drafted. It’s funny just how sticky initial evaluations/scouting reports can be. Still, will it translate?
I asked Eno Sarris about available pitch data for Mathews after his promotion to triple-A, Eno responded:
“94 mph fastball with average vertical movement, 94 stuff+, above-ave changeup and slider, locates everything well. 100-ish Stuff+ overall so not a bad package but not sure it’s dominant in the major leagues.”
I’m still wrestling with how to weight the different performance metrics. The Stuff+ type pitch modeling metrics obviously *directly* measure the specific velocity, spin, shape characteristics of the pitch itself, whereas the metrics you cite, including Whiff rate, Average Exit Velocity, HardHit%, etc., obviously involve how the batters perform against those pitches.
So, I’m not sure how to properly value/project Quinn Mathews. His overall numbers like walk rate, strikeout rate, ERA, etc. are all supportive of a #1 starter type performance level. If we drill down a bit more to get slightly more granular, Quinn’s HardHit%, AEV, Whiff rate, etc., are all still strong. But drilling all the way down to the most granular level and looking at Stuff+ type pitch modeling, he might appear to be more of a #3/4 type starter, though maybe a larger sample size will be more supportive of a higher projected ceiling.
Overall, I’m high on Quinn Mathews, but I’m still not confident that I understand his likely MLB performance level. Maybe it’s the less than elite fastball velocity or the stickiness of the initial scouting evaluation slapped on him during the draft, I don’t know. But, which level of granularity is most telling for Mathews? How do you balance those different levels of metrics to get a complete picture of both present and likely future performance level?
I guess the truth lies somewhere in between those metrics and I suppose the magic is in figuring out how to properly weigh those different metrics, along with relevant qualitative information, to identify what a pitcher is likely to become.
Anyway, good read and thanks!