MACK - MY FRIDAY OBSERVATIONS - MACK'S TOP PROSPECTS #12 - LHSP JONATHAN SANTUCCI - Mullins, BA, Alonso, Framber, Mangum, Donatelli, Soto, Benge, Ketel, Acuna, O'Neill, Trade, Top 10

 

I promised all of you that, as soon as the season ended, I would breakout and post my current Top 30 prospects.

This is performance based, not players that came to the Mets full of promise but have only produced butterscotch pudding. A perfect example of a player that didn’t make this list is catcher Ronald Hernandez. I still like the guy, but based on what he did in 2025, I don’t like him “top 30 guy”.

Nolan McLean, Brandon Sproat, and Jonah Tong _(maybe) are not on this list. They have graduated.

I will post them in each of my weekly Observations and In Focus posts… one player at a time… beginning with #30.

Today, we move to #12:

12.    SP     Jonathan Santucci

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

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.

MACK –

Santucci had a wonderful year in 2025. He showed remarkable control for a pitcher not known for it. And he did the one thing necessary to become a great pitcher in the majors someday… he stayed healthy.

ETA – right now I show him blocked at AAA-Syracuse (Jonah Tong, Jack Wenninger, R.J. Gordon, Joander Suarez, Jonathan Pintaro), but that could change in a heartbeat. For now, back to the Bing.   

Ca-Ching! Baseball America predicts big contracts for the top NY Mets free agents

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What Baseball America projects the top 5 Mets free agents earn on their next contract

Cedric Mullins - 1 year, $13 million

Half right on the one-year deal. For $13 million, Cedric Mullins is no steal. It hardly seems like a smaller AAV amount than if he continued at the pace he was at while with the Baltimore Orioles. How much more would a team really have paid for a declining player like him with a batting average regularly topping out in the .220s?

New Baseball America (BA) Grading:

Grade — Position Player Role — Starter Role — Reliever Role

75-80 — Franchise Player — No. 1 — N/A

65-70 — Perennial All-Star — No. 2 — N/A

60 — Occasional All-Star — No. 3 — Game’s best reliever

55 — First-division regular — No. 3/4 — Elite reliever

50 — Solid-average regular — No. 4 — High-leverage reliever

45 — Second division or platoon — No. 5 — middle reliever

40 — Reserve — Fill-in starter — Low-leverage reliever

30-35 — Org Player — Org Player — Up-and-down reliever

20-25 — Non prospect — Non prospect — Non prospect

 

PC - Ernest Dove

Pete Alonso and hitting with runners on base

mets360@substack.com

A season with 500 runners on base may not exactly be rare but it certainly doesn’t happen every year. In 2025, Alonso came up with 502 runners on base, 40 more than the second-place guy. It was the most runners on base for a hitter in a season since Albert Pujols came up with 525 runners on base in 2016.

It’s not fair to say that the only reason Alonso did well in RBIs is because of all the baserunners he had. Obviously, there were the home runs he hit. But Alonso was productive in his chances with ducks on the pond. His RBI% - (RBI-HR)/runners on *100 – was 17.53%, the fifth-best mark among the 36 players who came to bat with at least 400 runners on base.

Compare Alonso’s ’25 season with what he did the previous year. In 2024, Alonso had 34 HR and 88 RBIs. He came up with 437 runners on base and had a 12.36 RBI%. For his career, Alonso has come up with 2,915 runners on base and he has a 15.37 RBI%. There are 10 players since the 2019 season – Alonso’s first – to come up with at least 2,500 runners on base. Alonso has hit with the most runners on, 171 more than the player in second place, Matt Olson. But he ranks ninth with his 15.37 RBI%. Just above Alonso in eighth place is Juan Soto, with a 15.74% and the leader is Freddie Freeman with a 17.68% mark. 

'Perfect move' for Mets is signing 3.36 ERA lefty pitcher

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For the Mets, he wrote that it would be to sign left-handed pitcher Framber Valdez, formerly of the Houston Astros.

"The Mets have plenty of options to recover from their collapse in 2025 -- and it starts with pitching," Passan writes. "Bringing back Edwin Díaz makes sense, yes, but the more pressing issue is in the rotation. As reticent as president of baseball operations David Stearns is to sign starting pitchers to long-term deals, the alternative is to dip into their farm system and trade for them. And while that remains a possibility, one thing owner Steve Cohen has is money, and free agency is the optimal vessel to utilize it. So who better to go after than the most consistent starter available to join a rotation that is anything but consistent?

                  NY Mets predicted to add 2 frontline starters, here’s how they’ll do it

                  LINK

                  The first name that fits this Mets makeover is Framber Valdez. Over                       his last four seasons in Houston, he’s been the picture of dependability — 31 starts in three of those years, a sub-3.00 ERA in two, and a knack for making lineups look a little smaller by the seventh inning. He doesn’t live off swing-and-miss rates or wild velocity charts, yet he’s topped 160 strikeouts four straight seasons. Valdez is proof that command and consistency still win games. With an expected $200 million tag, only a few teams can keep up if the Mets decide he’s their prize.  

 

PC - JOHN CANADY

Two former Mets prospects who were handed away were among the best rookies last season

LINK

First we find Jake Mangum in center field. A light .296 batting average with 27 stolen bases this past year for the Tampa Bay Rays, the Mets traded him to the Miami Marlins prior to the 2023 season. He was the player to be named later in a deal which brought the Mets relievers Elieser Hernandez and Jeff Brigham. Due to injury, Hernandez never pitched a game for the Mets. Brigham appeared in 37 games but eventually ran out of gas and saw his ERA balloon to 5.26 by season’s end.

Mangum was a 4th round pick by the Mets whose light-hitting ways in the majors were exactly what he gave them in the minors. Ironically enough, he put together a fine rookie year in a season when the Mets could have absolutely used him in their carousel of center fielders. His defense grades well, making him valuable in a different role as well.

 

Jim Koenigsberger          @Jimfrombaseball

"I served in the Air Force, went into combat in October 1943 and flew 18 missions as a tail gunner on a B-l7. We were shot down before the D-Day invasion, on the first daylight bomber raid on Berlin, March 6, 1944.

That day 68 bombers were shot down.

We got hit, so the crew bailed out and I broke my ankle. I got captured and taken to Frankfurt.

I spent about 15 months in prison camps. We changed camps three times; the Germans kept moving us around so the Russians couldn’t liberate us.

They took us to Stettin, a port on the North Sea, and crammed us into the hold of a ship for two days. There must have been 2,500 of us in there, hot as hell, no water, no toilet. You had to go on deck to take a leak, but no way you could have a bowel movement.

When they took us off the ship, they chained two guys together at the wrists, and ran us about three miles to "Stalag Luft VI."

Another prisoner and I escaped, and were on the run 10 days before locals turned us in. The penalty for escaping was to work for a week cutting timber for fortifications, digging trenches and burial pits, and stuff like that.

The burial pits were for the Russians, who didn’t get a military burial like the Allies under the Geneva Convention; they were just dumped into the pit.

After about three months, the Russians liberated us in April, 1945."

Augie Donatelli

Soto’s Warning

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Mets star Juan Soto to 'work on improving defense' this offseason

All was kumbaya when Juan Soto inked a 15-year, $765 million contract with the Mets last offseason, making him the highest-paid athlete in major American sports history. It was the defining achievement of Steve Cohen's tenure as owner and a feather in the cap of former small-market GM David Stearns.

Then the Mets missed the postseason, and the cracks began to show. Nobody in Queens should be panicking at this point. That offense is a tank and Soto will finish third in NL MVP voting after he hit .263 with an impressive .921 OPS and 43 home runs. Only 27 years old, Soto is still one of the most well-rounded hitters in MLB, with a lengthy prime window ahead of him.

But there is one downside to Soto as a franchise cornerstone. He's a rapidly declining defender in right field. Soto handed the Mets -12 outs above average last season, in MLB's bottom percentile. That's tied with Nick Castellanos, which is not the company you want your best player to keep.

Soto, again, in 27. He's a major athlete, but all the muscle and precise, fluid motion at the plate does not translate to the outfield. In order to maximize their historic investment, the Mets need to stave off an inevitable move to DH for as long as possible. That's why Stearns and the Mets expect Soto to work hard to improve his defense this winter. It's his No. 1 focus, from the sound of it.

MACK – QUESTION. Has anyone asked Soto if he would like to eliminate this negative from his game and go full DH?

 

Carson Benge

CLICK HERE

No position is harder to fill in free agency than center field. Eight of the 10 best center fielders in baseball last season (by FanGraphs’ wins above replacement) made their big-league debut for their current team. (The exceptions were Trent Grisham and Jung Hoo Lee.) It was nine of 10 in 2024 (J.J. Bleday the exception), eight of 10 in 2023 (Cody Bellinger and Kevin Kiermaier), and nine of 10 in 2022 (George Springer) and 2021 (Starling Marte).

That means in the last five years, of roughly the 50 best center field seasons, 43 came from players either developed entirely in-house or acquired as minor-leaguers. Only four came from free-agent signings (Lee, Bellinger, Kiermaier and Springer).

Compare that to first base, where in the same time frame, just 21 of the best 50 seasons have come from in-house options (five of them by Pete Alonso).

There’s a reason why it’s so hard to add a center fielder in free agency

MACK -  PLEASE, PLEASE, PLEASE… don’t trade this guy!

 

Ketel Marte

CLICK HERE

Some new rumors make the possibility of the New York Mets making a blockbuster trade for Arizona Diamondbacks second baseman Ketel Marte a lot more realistic.

The 2025 season was not at all what the Mets or Diamondbacks expected. New York entered the year with aspirations to be in the World Series after reaching the NLCS in 2024. Instead, they wasted a great start to the season, had a historic collapse in September, and watched the playoffs from home in October.

Arizona was hoping the addition of ace Corbin Burnes would play a huge role in another run to the World Series, like they had in 2023. However, some big injuries — including to Burnes — and rough seasons from the pitching staff led to an 81-81 finish and another year missing the playoffs. Change is surely coming for both the Mets and D-backs.

In recent days, there have been rumblings that one notable move Arizona could make is trading three-time All-Star Ketel Marte.

MACK – I have a question… why bother drafting and nurturing high-bonus prospects if you are always going to trade for veterans? Yeah, I know. You need them for the trades. But I’m just sayin…

 

Luisangel Acuna

https://risingapple.com/ny-mets-unique-luisangel-acuna-david-stearns-endorsement?utm_campaign=FanSided+Daily&utm_source=FanSided+Daily&utm_medium=email&sc=82d672a86cde6b6d07b4ea29d553f634ede83f891ca0ec31d65e9e38eb81eba0

David Stearns was in midseason mode at this week’s GM Meetings. The more he talked, the more we were reminded of what an expert he is at saying words without really saying much else. Ahead of what should be another significant offseason for the New York Mets, Stearns offered an evaluation on some of the younger players on the roster.

Through a poker face, he evaluated Luisangel Acuna as “unique” with a high floor. He pointed out how Acuna can be useful to the Mets even without elite offensive skills which was one of the more honest assessments because based on last year’s performance, elite is one of the furthest adjectives to describe Acuna’s hitting abilities.

MACK – I can’t imagine the Mets finding a more versatile utility infielder thatn Acuna. He can field, he can run, he doesn’t suck with a bat in his hands, and he’s a ++ in both the clubhouse and dugout… but I said the same thing about that guy a year ago that had that hit song… 

Joel Sherman                  @Joelsherman1

Catcher Matt O’Neill, a Morristown (NJ) native and one-time Mets farmhand (2019-25), signed a minor league deal with the Diamondbacks that includes a spring training invite.

MACK – Wow. It’s been ages that O’Neill hasn’t been there for the Mets to call and ask him to play here and then play then, then… I’m really gonna miss this guy.

 

MetCast                         @MetCastPod

TRADE PROPOSAL:

 

Just Baseball                  @JustBB_Media

Just Baseball's Top 10 MLB Prospects