The New York Mets’ 2026 Bullpen Experiment: How a Group of Unknown Relievers Got Their Chance

The Backstory: How Jefry Yan Finally Became a Met

Imagine a baseball team watching a player for years, like a kid eyeing a toy in a store window. That’s exactly what the New York Mets did with Jefry Yan (pronounced "Jeff-ree Yan").

• 2023: Yan was pitching in Double-A (the second-highest minor league level) and struck out 39.1% of batters he faced — an incredibly high number.
• The Mets wanted to sign him as a minor-league free agent (a player free to sign with any team for a low-cost contract).
• But Yan chose Japan instead, so the Mets kept watching from afar.
• 2025: Yan signed with the Colorado Rockies, but they released him halfway through the season.
• Finally available, the Mets jumped at the chance.

Important Point
The Mets signed Yan to a two-year minor-league deal — unusual for a healthy pitcher. They didn’t even have him play in games at first. Instead, he spent months at their training complex in Port St. Lucie, Florida, working on his craft.

The Big Picture: A Bullpen Full of "Tryout" Relievers

By August 2026, the Mets’ closer (the pitcher who finishes close games), Devin Williams, was injured. So the team filled their bullpen (the group of relief pitchers) with a bunch of relievers on tryout contracts — guys looking to prove they belong.

The "Audition" Crew:

• Jefry Yan (lefty, famous for jumping celebrations)
• Kodai Senga (former starter, now reliever)
• Daniel Duarte
• Nate Lavender
• Jonathan Pintaro
• Chayce McDermott
• Jack Weisenburger
• Dedniel Núñez

Important Point
The Mets have struggled for years to develop their own relievers. Good teams often find hidden gems this way. The Mets’ goal? Just one or two of these guys turning into reliable options for next season would be a win.

As Mets executive Nate Horowitz put it:

“A lot of this is kind of shots on goal… some are going to work out, and some of them aren’t.”

Spotlight on Jefry Yan: The Celebrating Strikeout Artist

Yan turns 30 on Monday (August 17, 2026), but he’s pitching like a man on a mission.

• Recent performance: “He unlocked a new gear… kept his velocity up… improved the sinker, both breaking balls.” — Nate Horowitz
• Signature move: After a strikeout, he leaps into the air — a joyful, must-see celebration.
• Funny moment: On August 15, Yan thought he had a called third strike, jumped… but the ABS (Automated Ball-Strike system) showed it was a ball. Even the broadcaster laughed: “Now that was funny.”

Important Point
Yan’s celebrations didn’t factor into the signing decision much — the Mets just knew it was part of who he is. If he sticks around, his jumps might become a fan favorite.

Kodai Senga: From Struggling Starter to Lights-Out Reliever

Kodai Senga was a starter (pitches every 5–6 days) in Japan and early in his Mets career. But in 2026, he moved to the bullpen — and everything clicked.

Why the change works:

• Simpler role: One inning, max effort, no saving energy for later innings.
• Mental shift: “It’s do or die at that moment.” — Rosado on Senga’s mindset
• Prep adjustment: Used to pitching every 6th day; now learning to be ready back-to-back days (Mets plan to use him that way soon).

Important Point
The Mets are still in “discovery mode” with Senga as a reliever — but so far, so good.

Other Relievers Making Noise

Daniel Duarte (Righty)

• 18⅓ innings, 0.98 ERA (super low = very good)
• Throwing more first-pitch strikes than ever
• Holds left-handed batters to a .466 OPS (On-base Plus Slugging — lower = better; was .654 in 2023)

Jonathan Pintaro (Righty)

• Two scoreless innings Friday, stayed for Saturday
• Earlier in the year, a multi-inning outing meant a trip back to Triple-A (highest minor league) so the Mets could bring up a fresh arm
• Now? No pressure to be perfect — he can just pitch

Nate Lavender (Lefty)

• Attacks with strikes — no nibbling

Austin Warren (Righty)

• Was a revelation early in the season before getting hurt
• Currently on a rehab assignment (practicing in minors to come back)

Dedniel Núñez (Righty)

• Burst onto scene in 2024, got hurt, struggling to find form again — a reminder of how hard this is

Important Point
Role changes = freedom.
Earlier in the season, a bad outing meant a demotion. Now, in a lost season (team out of playoff race), these guys know they’ll stay up. They pitch with confidence, not fear.
“It’s a different mentality.” — José Rosado

Why This Matters: The Mets’ Long-Term Plan

Finding good relievers cheaply — from:

• Minor-league free agency (like Yan)
• The farm system (homegrown)
• The waiver wire (players other teams dropped)

…lets the Mets avoid constantly spending big money on free-agent relievers.

Important Point
One or two success stories from this group go a LONG way.
Maybe it’s Yan. Maybe it’s Duarte. Maybe it’s someone we haven’t noticed yet.
But if even a couple stick, the Mets build a cheaper, deeper, homegrown bullpen — something the best teams do every year.

Summary

• The Mets signed Jefry Yan after tracking him for years — he’s now pitching well and entertaining fans with his signature jump celebrations.
• With closer Devin Williams injured, the Mets are auditioning 8+ relievers in the final 6 weeks of a lost season.
• Kodai Senga has transformed into a dominant reliever — throwing harder, simpler, and happier.
• Daniel Duarte, Jonathan Pintaro, and others are thriving with new roles and no fear of demotion.
• The goal: Find 1–2 keepers for 2027+ so the Mets can stop rebuilding their bullpen every winter.

FAQ

1. What is a "reliever" in baseball?

A reliever (or relief pitcher) comes into the game after the starting pitcher, usually for 1–2 innings. They specialize in short, high-intensity bursts.

2. What’s the difference between a starter and a reliever?

• Starter: Pitches every 5–6 days, tries to go 5+ innings, paces themselves.
• Reliever: Can pitch back-to-back days, throws max effort for 1 inning, no need to save energy.

3. What is "ABS" (the Automated Ball-Strike system)?

It’s a computer system that tracks whether a pitch is a strike or ball — used in some minor leagues and tested in majors. It’s like a robot umpire for balls and strikes.

4. Why does a "lost season" help these relievers?

When a team is out of the playoffs, they don’t need to win every game. They can keep young/unproven pitchers up after rough outings instead of sending them down. This builds confidence and experience.

5. What does "shots on goal" mean in this context?

It’s a hockey metaphor: You take lots of shots (sign lots of low-cost relievers), knowing most won’t score (work out) — but a few might, and that’s all you need.