Top 25 Mets Prospects for 2023: RHP Junior Santos (21)

Name: Junior Santos
Position: RHP
Born: 8/16/2001
Height: 6’7”
Weight: 245 lbs.
Bats/Throws: R/R
Acquired: IFA, June 2, 2018 (Santiago, Dominican Republic)
2022 Stats: 26 G (23 GS), 116.2 IP, 126 H, 67 R, 58 ER (4.47 ERA), 44 BB, 105 K, .341 BABIP (High-A)

A native Santiago in the Dominican Republic, Junior Santos quickly stood out from his baseball contemporaries because of his size; when he turned sixteen, the young right-hander stood 6’6”, prompting the Mets to sign him for $275,000 on June 2, 2018, the very first day of the 2018-2019 international free agent signing period. The organization was aggressive with Santos, assigning him to the Dominican Summer League immediately instead of opting to wait to have him debut professionally the following season as is generally the case with most international rookies. He made 11 appearances for the DSL Mets that year, making ten starts and posting a 2.80 ERA in 45.0 innings, allowing 35 hits, walking 6, and striking out 36. Continuing to challenge Santos, who by this point had grown an additional two inches or so, the Mets sent him stateside at the end of the season. Appearing in three games for the GCL Mets, the 16-year-old pitched five innings in three outings, posting a perfect 0.00 ERA with 4 hits allowed, 0 walks, and 3 strikeouts.

The Mets left Santos on this extremely aggressive developmental track in 2019 and assigned him to the Kingsport Mets when their season began in late June, the youngest pitcher in the league. Starting fourteen games, the 17-year-old Santos threw 40.2 and posted a 5.90 ERA, allowing 46 hits, walking 25, and striking out 36. After missing the 2020 season due to the COVID-19 pandemic, Santos returned to the mound in 2021, where he was assigned to the St. Lucie Mets. The third-youngest player in the Low-A Southeast, the right-hander posted a 4.59 ERA in 96.0 innings, allowing 108 hits, walking 38, and striking out 79, not that far off from the league average 4.53 ERA with 10.1 hits per nine innings, 3.6 walks per nine innings, and 7.4 strikeouts per nine innings. He was promoted to Brooklyn for the 2022 season and posted a 4.47 ERA in 116.2 innings, allowing 126 hits, walking 44, and striking out 105, once again not that far off from the South Atlantic League pitching averages of a 4.48 ERA with 8.3 per nine innings, 4.1 walks per nine innings, and 9.9 strikeouts per nine innings.

Santos throws from a slingy low- three-quarters arm slot, utilizing a short, simple, delivery. Santos is generally able maintain his balance and avoid herky-jerky movement during his leg lift and drive off of the mound, but sometimes has trouble maintain his arm slot, especially when throwing his secondary pitches as he has a tendency to guide them like many young pitchers do.

His fastball regained a bit of the giddyap that it lost in 2021, sitting 93-96 MPH; in 2021, it averaged 93 MPH, whereas in 2019, it sat 94-95 MPH. His fastball has slight arm-side movement, but more importantly, he can sink it. Santos’ sinker averages between 16 to 29 inches of vertical movement and 11-20 inches of horizontal movement, averaging 2300 RPM and a high spin efficiency. The right-hander has become more confident with the pitch, and his ground ball rates have steadily increased, from 29.4% with the Kingsport Mets in the Appalachian League in 2019 to 49.1% with the St. Lucie Mets in the Low-A Southeast in 2021 to 58.7% with the Brooklyn Cyclones in the South Atlantic League in 2022.

Complementing his fastball are a slider and a changeup. His slider sits between 77-86 MPH and features gyroscopic spin, possessing 0-3 inches of horizontal movement and 29-37 inches of vertical drop. The pitch induces the majority of Santos’ swings-and-misses, but he often has trouble commanding it. His changeup lags even further behind in its development than his slider, as highlighted by the high variance in its movement- the pitch generally had anywhere between 6-18 inches of horizontal movement and 20-30 inches of vertical drop- and velocity- ranging anywhere between 82-90 MPH. Like his slider, he still has trouble commanding it, but unlike the slider, the pitch did not induce as many swings-or-misses and batters make more hard contact off of it.

Steve Says:

I like Junior Santos, but it’s hard for prospect fatigue to not set in. He’s been in the organization for a few years now, but the progress just really isn’t there. The fastball is still decent but hittable. The breaking stuff is still barely passable. Three years younger than league average, his 2022 numbers overall were more or less on par for the South Atlantic League, so it’s not like Santos is bad or anything, but I just wish a light bulb would finally go on. Here’s hoping that happens in 2023.

Lukas Says:

My skepticism on Santos from years past remains, even though he posted a career-best strikeout rate and a career-high in innings at High-A this season. He’s young(-ish), still very tall, and reportedly has some interesting pitch characteristics, though the Mets have not quite optimized them as of yet. Perhaps I’m underrating him based on the stats, or perhaps he’s another arm that’s been overrated based on size and projection. A 2022 test at Double-A will help reveal which is the case.

Ken Says:

Santos spent the entire season pitching out of the rotation in Brooklyn, where he generally held his own against significantly older competition, even if his topline numbers left something to be desired. He ended the season with an ERA well above four, a strikeout per nine innings rate below nine, and a walks per nine inning rate well above three. He excelled at keeping the ball in the park in 2022, allowing just 0.31 home runs per nine innings, but that may have more to do with making the majority of his starts against the wind on Coney Island than innate talent. Santos’ frame and fastball velocity still make him an intriguing prospect, but he will need to refine his command and miss more bats if he is to remain a starter moving forward.

Thomas Says:

Despite only being 21, Santos feels like he’s been around for 10 years. The 6’7 righty was pushed rather aggressively throughout his time in professional ball, playing Rookie ball in Kingsport at 17, at Single-A as a 19 year old, and Double-A as a 20 year old. While that is interesting, he’s never really performed at any level, coming into the year with a 4.27 career ERA. While those promotions certainly taught him some things, it’s also high time for a good season out of him considering his experience at these levels.