What goes into creating a successful bullpen? Surely teams need to spend heavily to acquire as many high-priced and established leverage relievers as possible to have success, correct? Well, not necessarily.

The 2025 Dodgers’ World Series Roster contained only one primary reliever making over $10 million must have been an anomaly, as long as you ignore the 2024 Dodgers’ World Series roster where their highest-paid reliever, Joe Kelly, who was making $8 million, was not even on the roster. The 2023 Rangers’ top reliever was making $6.25 million dollars. The 2022 Astros are the most expensive bullpen of recent years, with two relievers making over $10 million and Hector Neris making $8 million.

In addition to that, the Brewers and Rays year after year have some of the least expensive bullpens, but rank among the top performers in the sport. Not that having an expensive bullpen full of established relievers is a bad thing to be clear. Just that the league has seen that it is not a secret equation to build a great bullpen.

So what is the similarity between these high-performing bullpens if teams are not just stocking up on the most expensive and established arms like they are infinity stones?

Mets president of baseball operations David Stearns explained what goes into a good bullpen at the Winter Meetings before the 2024 season, saying, “I think there’s a desire to have a diversity of looks and stuff out of a reliever. Velocity is a part of that. Velocity is not the entire package there. So, yeah, I’d like to have a couple of guys who can really bring it out of the pen. I’d also like to have some different looks. And there are plenty of guys throwing in the high 80s that are doing a good job in the bullpens these days.” In September of that 2024 season, Will Sammon of the Athletic broke down how that philosophy shaped the Mets bullpen.

At first there were some growing pains for the Mets, who under Stearns had to largely build that bullpen from scratch. Their bullpen across 2024 ranked seventeenth in ERA and thirteenth in Fangraphs WAR. In 2025, they were fifteenth in ERA but were sixth in WAR. So far in 2026, it is sixth in ERA and eighth in WAR.

Mets bullpens have also changed significantly as each individual season has gone on. Stearns has no issue cutting bait with a reliever if it is not working and adjusting around what is working. After a rough first few months, in the second half of 2024 the Mets were eleventh in ERA and tenth in WAR. Before the 2025 trade deadline, the Mets were sixth in ERA and sixth in WAR. If there is ever an argument for not prioritizing a name value reliever, the Ryan Helsley trade is the poster child.

Since the 2026 trade deadline, despite trading away most of their established arms and losing their closer, Devin Williams, to injury, the Mets have the sixth-best ERA and are eleventh by WAR with a bullpen full of names that make many Mets fans each night look at the box score and go “who?”

The New Closer

Let us start at the top with the current closer Kodai Senga. After struggling to return as a starter in 2026, undergoing yet another injury, the Mets have finally converted Senga into a single-inning reliever. Across six games, he has a 1.50 ERA and a 1.00 WHIP with four saves in four opportunities. It is a very small sample size, but we have seen how pitching in short outings drastically improves his pitch mix and effectiveness.

In this role, he is able to juice his velocity up to 97 miles per hour, which creates further separation from his forkball, making that pitch play up. Heading into August 21, that forkball was running a 66.7% whiff rate. He has thrown his fastballs and forkball 90.6% of the time as a single-inning reliever, seldom mixing in his sweeper, slider, and cutter. He is at his best when he is throwing his best pitches more.

His forkball is such a unicorn in baseball, and his ability to pair that with a high-velocity fastball as a reliever puts him alone at the top here.

Low Slot Pitch Diversification

Jonathan Pintaro (23 degrees) and Austin Warren (26 degrees) are both right-handed pitchers who throw six different pitches. The arm slot and ability to flummox batters with a deep pitch mix is all these two share in common, though. Pintaro is a cutter-heavy starter who throws three different fastball shapes while mixing in a changeup, sweeper, and curveball. This has helped him pitch to a 3.72 ERA and 1.09 WHIP. Since returning to the bullpen in August, he has pitched to a 1.29 ERA.

Warren meanwhile relies heavily on his sweeper as his primary pitch while his sinker generates weak contact on the ground. He goes to his four-seam fastball when he wants whiffs and mixes in a curveball, cutter and changeup. He was dominating before the two outings that led to his injured list trip, and his return to the bullpen is welcomed.

Glove Side Lefties

Both Nate Lavender, with his 0.00 ERA and 0.39 WHIP, and Jefry Yan, with his 4.26 ERA and 1.89 WHIP, throw sliders with good glove side movement and fastballs with roughly 17 inches of induced vertical break and six inches of arm side movement. Where they differ the most is velocity, with Yan topping out over 100 miles per hour and Lavender sitting around 92-93. Yan throws two fastball shapes between his sinker and four-seam while Lavender throws a sweeper and a changeup. Both have arm angles in the 40s and have success built around strong whiff rates.

I would argue that Lavender’s deceptive delivery, pitch mix, and extension should make him the better option for leverage – something that the most recent outing potentially exemplifies – but in general their differences complement each other. So far, Nate Lavender has made the full argument to be in the 2027 opening day bullpen while Jefry Yan is definitely in the conversation for the second lefty spot. At the worst, with his options, he has the opportunity to earn plenty of innings over the next few years.

Chase the Sweeper

While Lavender and Yan have built their games around high whiff rates, neither Daniel Duarte nor Jack Weisenburger generate much swing and miss, both sitting around 23%. This does give me some pause in projecting their future success, as chase rates around 40% like they are both running tend not to be sticky, but being able to cycle up and down relievers with this trait is beneficial to the overall bullpen build. Weisenburger was running a 56.3% chase rate on his sweeper before he got optioned, while Duarte has been running a 44.9% chase rate. Weisenburger also gets significant chase on his sinker, while Duarte gets significant chase on his cutter. Duarte has been nearly perfect with the Mets running a 0.82 ERA and 0.59 WHIP, while Weisenburger’s 2.08 ERA and 1.15 WHIP across his 4 1/3 innings of work was a great first look in the majors for the 28-year-old.

Overpower With Stuff, Wherever it Goes

Chayce McDermott has some of the best stuff of any Mets reliever, with stuff models from both TJStats and Fangraphs logging him with multiple elite-ranking pitches. His issue is that he struggles to command most of his pitches. With the Mets, he has begun to attack the zone more, but he is still below average. But when he is commanding his pitches, he overpowers hitters, running both high whiff rates and significant chase. Multiple teams now have taken a shot on him because of how he can pepper the top of the zone while also getting outs on pitches outside the zone. He also tunnels his cutter and slider well, which helps him generate both whiff and chase on both pitches.

Over the Top Weak Contact

It may be a stretch calling Xzavion Curry over the top, but his 56-degree arm angle is on the higher side. Tobias Myers and his 64-degree arm angle fit that better; he will likely get some time in the bullpen to end the year, is more over the top but also fits a lot of what I have to say about Curry.

Curry does not rely heavily on whiff or chase and typically pitches to contact. He utilizes a deep pitch mix and multiple breaking balls to generate weak contact, mostly in the air. His unusual arm angle helps him to confuse hitters even when he sees them a second time. Curry was optioned but likely will get more innings as needed.

A Simple Power Pitcher

I am not going to pretend the results have been good for Dedniel Núñez in his 5 1/3 innings of work with his 10.13 ERA and 2.25 WHIP. At the same point, he is returning from Tommy John surgery and probably deserves a bit of an adjustment period.

What he does provide is both velocity and spin to overwhelm hitters. His spin rates on his slider are not the elite level they were before surgery, but they have increased since his first rehab assignment and ideally will continue to climb. He is still overpowering batters with a 45.5% chase rate and 47.1% whiff rate on the pitch. He has thrown as hard as 98.4 miles per hour on his fastball and is running a 30% chase rate, though the swing and miss is not there yet. Both pitches still rate above average, and he is attacking the zone and limiting walks.

What Can We Learn From This?

What we see here is how a bullpen that has many different looks can confuse hitters and keep them off balance. Imagine going from Yan throwing 100-mile-per-hour fastballs and heavy sliders from the left side to Daniel Duarte peppering six different pitches around the zone and medium to low velocity. Then the next night you see Dedniel Núñez overpowering with velocity and spin from the right side, followed by Nate Lavender throwing from the left side with a deceptive delivery that plays up his lower velocity mix and then handing it off to Senga and his unique forkball to close out the game.

When you have a bullpen that complements itself well, you can have success no matter the dollar amount. The Mets bullpen since Devin Williams went on the injured list has sat around only $20 million, and the majority of that is Kodai Senga. He is also the only truly established arm in the bullpen, and even he is relatively new to being a reliever.

Finally, being able to adapt, ride the hot hand, and adjust to changes across the bullpen will help the Mets continue to have success. We will likely see multiple more arms join this bullpen with guys shuffling up and down as the Mets continue to evaluate who should be on their 2027 roster. But so far, they have performed as well, if not better than, they did with Luke Weaver, Brooks Raley, and Huascar Brazobán, all of whom have not performed as well with their new teams as they did with the Mets.