MACK - SUNDAY OBSERVATIONS - MACK'S #6 PROSPECT - SP ZACH THORNTON - Jorge Loyola, Jacob Reimer, Jonah Tong, Seranthony Domingues

 

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 #6:

6.     SP     Zach Thornton

LHSP        6-3        170        24/yrs in July

5^th round pick 2023 – Grand Canyon U. (Guess Where?)

2025 – A+/AA:   14-ST, 6-2, 1.98, 0.81, 72.2-IP, 78-K, 11-BB

Zach Thornton is a highly regarded left-handed starting pitcher in the New York Mets' minor league system.

At 23 years old (born January 17, 2002, in Winona, Minnesota), he's emerging as one of the organization's most promising arms, particularly noted for his elite command, control, and ability to dominate lineups without elite velocity.

Standing at 6'3" and 170 pounds, Thornton profiles as a potential back-of-the-rotation starter at the MLB level, with scouts praising his deceptive delivery.

Thornton grew up in Lawrence, Kansas, and honed his skills in summer collegiate leagues before transferring to Grand Canyon University (NCAA Division I) for his junior year in 2023. At Grand Canyon, he earned All-WAC second-team honors as a starter, posting a 3.87 ERA over 88.1 innings with 91 strikeouts and just 18 walks—showcasing the command that would define his pro career.

The Mets selected him in the fifth round (159th overall) of the 2023 MLB Draft, signing him for $350,000. Prior to the draft, Thornton had a decorated JUCO career at Barton Community College, where he was named first-team all-conference, conference Pitcher of the Year runner-up, first-team all-region, and third-team All-American as a sophomore in 2022. He also pitched in the Appalachian League (Elizabethton River Riders) and MLB Draft League (Mahoning Valley Scrappers), boosting his stock with scouts.

Thornton's pro debut in 2023 was solid but unremarkable: he split time between the Florida Complex League Mets and Single-A St. Lucie, going 1-1 with a 4.50 ERA in 22 innings.

The real breakout came in 2025, where he dominated across High-A Brooklyn (South Atlantic League) and Double-A Binghamton (Eastern League).

Overall Stats (as of injury in August 2025): 8-2 record, 1.53 ERA, 0.89 WHIP, 24.4% K-BB% rate (16th-best among minor leaguers with 12+ starts), and a sub-2.00 FIP. He ranked among the top 16 minor league pitchers with an ERA under 2.00.

High-A Brooklyn (April-May): 3-0, 0.44 ERA in four starts (20.2 IP), with 24 strikeouts and just 2 walks. Earned South Atlantic League Pitcher of the Month for April.

Double-A Binghamton (May-August): 5-2, 2.13 ERA, including gems like 6.2 IP of one-run ball (8 K's, no walks) and a career-high 7 IP shutout (3 H, 6 K, 0 BB). Named Eastern League Pitcher of the Week for May 19-25.

His 2025 season quietly placed him among the Mets' top pitching prospects, behind headliners like Jonah Tong and Brandon Sproat but ahead of many in raw effectiveness.

Thornton's arsenal isn't built on velocity but on deception, location, and sequencing. His delivery—described as "all movement"—creates late life on his pitches, leading to high whiff rates despite modest speeds. He commands all four offerings well, rarely exceeding 90 pitches per start.

Fastball - Four-seam with significant induced vertical break (16.1 inches) and spin rates of 2,200-2,400 RPM for deception. Sits low-90s, tops out at 93-94 mph. Primary pitch (50-60% usage); plays up due to arm action and command. Generates swings-and-misses despite average velo.

Slider - Mid-80s sweeper with sharp horizontal break; his go-to out pitch against righties.  25-30% usage; above-average command allows him to bury it low-and-away. Complements fastball well.

Curveball - 12-6 breaker for depth and change of pace; used to steal strikes early in counts. 10-15% usage; effective for tunneling with fastball-slider.

Changeup - Fading action to jam lefties; developing but inconsistent. 5-10% usage; more of a show-me pitch, but improving

Cutter (emerging) - Hard horizontal slice added in 2025 for variety against contact hitters. Low usage (~5%); helps shorten plate appearances and set up other pitches.

Scouts note his fastball-slider combo as plus, with the full mix giving him a "crafty lefty" profile similar to a young Jamie Moyer but with better strikeout upside. Areas for growth: Adding velocity (he's young and projectable) and refining the changeup for same-handed matchups.

Outlook - Thornton embodies the Mets' emphasis on polished college arms under David Stearns. If he stays healthy, he's on track for a big-league debut by 2027, potentially as a reliable No. 4-5 starter.

Mack – this is another of those great Mets minor league starters that get little press, due to the emphasis on The Three Amigos (McLean, Tong, Sproat). Don’t be surprised if he sneaks into the open day 2027 roation as an SP4-5.

Jeff Duda                  @INTLBaseball24

Jorge Loyola, who is participating in Japan’s winter league, is from Peru and played for them in U23 World Cup qualifiers. The biggest arm to ever come from Perú. His fastball nearly touches 105 MPH(!)

Running From The OPS                    @OPS_BASEBALL

We saw a full season out of Jacob Reimer in 2025, and the 21-year-old certainly didn't disappoint. He slashed .282/.379/.491 with 17 HR, 32 2B, an .870 OPS, and a 157 wRC+. He has an advanced eye at the plate and pairs it with excellent swing decisions. This system is loaded!

 

MLB Prospects to Watch as Potential Centerpieces in Winter Meetings Trades

CLICK HERE

RHP Jonah Tong, New York Mets

San Diego Padres v New York Mets

Jim McIsaac/Getty Images

B/R Prospect Rank: No. 3 NYM, No. 34 MLB

Stats (AA/AAA): 22 GS, 1.43 ERA, 0.92 WHIP, 47 BB, 179 K, 113.2 IP

Scouting Report: Despite making his MLB debut on Aug. 29 and spending the rest of the season in the majors, Tong still led all minor league pitchers with 179 strikeouts.

He has an elite fastball, plus changeup and a high-spin curve, all delivered from an over-the-top arm slot that is reminiscent of Tim Lincecum.

Tong had a 7.71 ERA in 18.2 innings in the majors, but he flashed upside with 22 strikeouts and a more palatable 4.31 FIP.

Why He Could Be Traded: The Mets have three exciting young arms in Tong, Nolan McLean and Brandon Sproat, but it's unlikely they will trust all three to hold down rotation spots in 2026.

With the front office clear in win-now mode, that could mean flipping one of those arms to address a need elsewhere, like center field.

Former Phillies closer connected to Mets in MLB free agency

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Seranthony Dominguez

As a free agent again this winter, the 31-year-old should have a decent market. When examining potential landing spots for the veteran, Josue De Jesus of Rising Apple believes that Dominguez could be an option for the New York Mets, a team rumored to be interested in adding a few bullpen arms.

“Bullpen volatility is a constant in baseball, making Seranthony Domínguez a fascinating Tier 5 target for the Mets’ relief corps. The hard-throwing righty pitched 62.2 innings across 67 games in 2025, registering a solid 3.16 ERA and an encouraging 1.28 WHIP. He continued to rely on elite strikeout ability, punching out 79 batters, which translates to an exceptional K/9 rate of over 11.3 for the season.

“However, Domínguez’s history is marred by injury-related shutdowns and command inconsistencies, explaining his Tier 5 status. His career ERA stands at a strong 3.50, backed by a phenomenal 10.6 career K/9,” he wrote.

 

If there was one issue for the Mets a year ago, it was on the mound, and that’s something they will have to fix.

 

Unprotected From the Rule 5 Draft

https://www.justbaseball.com/prospects/most-surprising-prospects-left-unprotected-rule-5-draft/?s=03

Hayden Mullins (LHP) – Boston Red Sox

2025 Stats: 22 G (21 GS), 101.2 IP, 2.21 ERA, 3.44 FIP, 123 K

Hayden Mullins is going to make a major league organization pretty happy when they get to submit the card to draft him in the Rule 5 this year.

 

The left-handed pitcher continued to rise up Red Sox prospect rankings as the season went on in 2025, putting up a 10.9 K/9 by season’s end. He is the traditional lefty, in that he lives in the low-90s with his fastball, topping out around 95 mph, but he does possess a strong slider/change-up combination that works off the same plane, creating unique deception to opposing hitters.

Even if he is not able to stick in the back of a rotation in the big leagues, Mullins would serve well as a bulk arm in a team’s bullpen.