MACK - Top 28 Prospects - #17 - RHSP - Jonathan Santucci

 

The excitement about the Mets' prospect pipeline has been building year over year as the team improves their domestic and international scouting.  Many of the Mets' picks are being discussed throughout baseball, so Mack has boiled it down to the top 28 to give the readers a glimpse into the team's future.  This series will run for 28 days, counting down from #28 to #1.  The entire list can be viewed by clicking "2026 Top 28 Prospects" on the top menu bar.

17.    Jonathan Santucci

2025:        A+/AA:  25-G, 23-ST, 9-4, 3.06, 1.15, 117.2-IP, 41-BB, 138-K

GROK -

Jonathan Santucci is a highly regarded left-handed pitching prospect in the New York Mets organization, selected in the second round (46th overall) of the 2024 MLB Draft out of Duke University.

Born on December 28, 2002, in Leominster, Massachusetts, the 6'2", 205-pound southpaw bats and throws left-handed.

Santucci signed for the full slot value of $2,031,700

Attended Phillips Academy in Andover, Massachusetts, where he was Massachusetts' top prep pitching prospect in 2021. He also showed athleticism as a two-way player, occasionally playing center field and right field.

At Duke, he transitioned fully to pitching and earned a spot in the weekend rotation as a freshman in 2022, posting a 4.17 ERA over 41 innings with 58 strikeouts and 20 walks.

His sophomore year (2023) was abbreviated by a fractured elbow requiring surgery to remove bone chips, limiting him to 29.1 innings with 50 strikeouts but highlighting his strikeout prowess (13.9 K/9 career at Duke).

 As a junior in 2024, he rebounded as Duke's Friday night ace, logging a 3.41 ERA in 58 innings across 13 starts with a 35% strikeout rate but a 14% walk rate—issues with control that contributed to high pitch counts and kept him out of the first round of the draft. A mid-season rib injury (non-throwing side) also sidelined him for three starts late in the year.

Professional Career

Santucci didn't pitch in the Florida Complex League (FCL) after signing in August 2024.

In 2025, his first full pro season, he advanced rapidly: starting in Low-A, moving to High-A, and reaching Double-A Binghamton by mid-year, where he was activated as of August.

Health remains a watch point, given his injury history, but his athleticism and mechanics suggest he could improve his below-average control (scouted at 45/80) to average levels with coaching.

Pitch Repertoire

Santucci's arsenal is built around swing-and-miss stuff, earning him a career 13.9 K/9 in college. He works from a high arm slot with a flat approach angle, generating carry and deception.

Scouting grades (on the 20-80 scale) include: Fastball 60, Slider 60, Changeup 55, Control 45, Overall 45.

Four-Seam Fastball

92-96 mph

Features impressive induced vertical break (carry) and armside run; elite against college hitters for whiffs due to flat plane and high slot. Effective to both sides of the plate.

Primary pitch (50-60% usage); challenges with command lead to walks and deep counts. Mets may add a sinker or cutter for early-contact outs.

Slider

82-85 mph (low-80s at times)

Wipeout breaking ball with sharp, two-plane break (lateral and vertical); platoon-neutral, devastating vs. right-handers (56% whiff rate in 2024). Snappy at best, but can flatten if overthrown.

Key secondary (30-40% usage); thrown with fastball arm speed for deception; equalizer for his control issues.

Changeup

Mid- to upper-80s

Shows arm-side fade and vertical tumble; above-average potential with good arm speed replication, but inconsistent command.

Tertiary pitch (9-10% usage); mostly vs. right-handers later in games; sparingly thrown but effective when located.

 

11-7-2025

JUST BASEBALL

10. Jonathan Santucci – LHP – (Double-A)

Height/Weight: 6’2″, 195 | Bat/Throw: L/L | 2nd Round (46) – NYM (2024) | ETA: 2027

A southpaw with an exciting fastball, slider combination Santucci had plenty of first round buzz heading into his draft year before a rib injury and command issues pushed him to the second round. Santucci looked like a first round talent in his first pro season, cutting down the walk rate and improving as the season progressed, dominating at Double-A in the second half.

Arsenal

Santucci gets above average carry on a 94-95 MPH fastball, generating above average whiff numbers within the zone. His gyro slider pairs well with his fastball with the vertical action to make it effective to both lefties and righties, with strong whiff and ground ball rates. He commands the slider better than any of his offerings, with a strike rate of nearly 70% in 2025.

The southpaw is still looking for a consistent third offering, with his low 80s curveball looking more reliable than his firm upper 80s changeup. The shape of his curveball is similar to that of Noah Cameron’s, flashing at least average, but without much consistency and less than 10% usage.

Outlook

Santucci’s 2025 season has him rising up the Mets ranks as the best left-handed pitching prospect in their system. Though the control improved mightily in his pro debut, Santucci’s command is still a work in progress, with a strike rate of just 61% on all offerings other than his slider.

The fastball, slider combination gives Santucci the floor of an effective left-handed reliever, but his improved ability to throw strikes and at least signs of a third offering have earned him plenty of runway as a starting pitching prospect where he could be a quality No. 4 starter if it comes together.

 

11-23-2025 –

Angry             @AngryMike24

Mets Jonathan Santucci had 19 outings in 2025, allowing 3 ER or fewer for HI-A & AA:

97.2 IP | 23 ER | 52 Hits | 30 BB | 116 K | 2.13 ERA | 0.84 WHIP

29% K-Rate for ‘25

#’s on par or better than any LHP ranked among Top 100, but Santucci remains unranked.  Absurd.

 

12-20-2025 –

MACK/MM

Jonathan Santucci – thanks to Brennan, I didn’t miss on this guy. Big time Friday Night starter out of Duke. Started out with 15-G/13-ST with A+ Brooklyn (3.46), but ended strong with AA-Binghamton (10-ST, 2.52). Overall, a whopping 138-K in 117.2-IP. Could force his way into the opening day AAA-Syracuse rotation, but I have him first returning to AA-Binghamton to probably help create the strongest rotation n that league.

 

12-5-2025

Angry Mike/MM

JON SANTUCCI -> He’d be the #1 SP prospect for a lot of other franchises, he’s penciled for AAA.

-> What new pitches will he deploy in 2026? Will we see an increase in usage of his curveball and changeup in 2026? Any chance Santucci gets a look as a RP if the #Mets want to add another dynamic weapon for the bullpen?

 

1-13-2026

Angry Mike/MM             @AngryMike24

Mets Jonathan Santucci final 21 Outings & Z. Thornton 2025 Stats compared to MLB Pipeline’s Top 10 LHP:

<->  Mets J. Santucci -> Final 21 Outings in ‘25: Hi-A & AA:

-> 16 / 21 Outings of at least 5+ IP

-> 14 / 16 Outings of 5+ IP allowed 2 ER or fewer

105.2 IP | 28 ER | 124 K | 36 BB | 76 H | 2.40 ERA | 1.07 WHIP

->  29% K-RATE  |  8.5% BB-RATE