Los Bomberos are a policy success

In case you missed it, last night the Seattle Mariners debuted a new nickname/branding title for their bullpen: Los Bomberos - The Firefighters.

To accompany the new title, which was presumably encouraged in some capacity by the club to allow them to provide a more hype-infused in-game experience at T-Mobile Park, the M’s indeed showed off a new intro for what will presumably be any initial call to the bullpen, or perhaps saved for high-leverage moments.

The first reliever to receive the treatment was, aptly, its originator. Per last night’s broadcast, 23-year-old RHP Andrés Muñoz suggested the name, which the players then voted in favor of. While your mileage may vary for self-ascribed nicknames, in my experience it’s less chide-worthy when applied to a group. It’s also somewhat impressive that the club went along with the suggestion of their youngest pitcher (and third-youngest player at any time this season after Julio Rodríguez and Jarred Kelenic). What’s more impressive than the title is the performance of the unit itself.

In the majority of Seattle’s time in the Jerry Dipoto era they’ve had effective bullpens, in high-leverage circumstances in particular. Individual stars like Edwin Díaz and Paul Sewald have helped this, of course. However, this year’s group has been a notch above those who came before, including last year’s vaunted club.

It can be tricky to track production from relievers by bulk stats, particularly as their usage is deeply contextual. That’s why that Win Probability Added number is so staggering for the 2022 club. While stats like Wins Above Replacement and even ERA, FIP, and DRA obviously endeavor to encapsulate pitcher performance, the role of one reliever to another can vary wildly in terms of importance. For instance, Casey Lawrence throwing 42.0 innings of 5.57 ERA ball in 23 games in 2017 was unequivocally bad, but because he pitched predominantly in games the M’s were already losing or winning by a healthy margin, he only resulted in -0.53 Win Probability Added, canceled out and then some by Nick Vincent, whose 1.74 Win Probability Added in just 22 more innings came as a result of key performance when it was most influential on the team.

Similarly, this season’s worst performers overall (by either WAR metric) are players like Sergio Romo, Tommy Milone, Ryan Borucki, and Yohan Ramírez, whose usages were, outside of extra innings games and a few injury-thinned stretches, lower leverage circumstances. Only Drew Steckenrider, currently getting his feet back beneath him in Triple-A Tacoma, has had a truly devastating season in high-leverage moments. The majority of Seattle’s pen, by contrast, is thoroughly in the positive, including Diego Castillo and Paul Sewald both slotting in the top-15 in MLB in WPA for relievers. Comfortably positive, however, are Muñoz, Matt Brash, Erik Swanson, and Matt Festa.

Seattle’s ability to manufacture quality bullpen arms was at the core of their overachieving clubs in 2018 and 2021, and indeed the only season in the Dipoto era with an intentionally “contending” team and a bullpen that was not among the best in the league by WPA was 2017. That bullpens will defy projections and be volatile is one of the truisms of MLB, so Seattle’s ability to frequently outperform expectations with their pens has perhaps been more important than any other individual player development achievement in this regime’s time. Not only has it kept the club in contention, the improvements of unsung arms have helped stock the rest of the roster and afforded them the luxury to deal prospects without as much fear of leaving the system without depth as was done in Dipoto’s first few seasons.

Not every player has become a Díaz or Sewald, but turning a Double-A starter without a third pitch and a Mets castoff who sought out the organization specifically for their reputation of quality pitching development into bona fide bullpen aces is a lofty bar. To be able to run out a pitcher like Swanson, Festa, or even Penn Murfee with confidence as a mid-leverage arm is a luxury few teams have. The eminence of Sewald, Castillo, and Muñoz has also allowed Seattle to eschew the allure of a traditional closer role in totality, favoring using any of their three best arms as a stopper in a key moment, a late-inning matchup with the heart of the order outside of the 9th inning, or any other key period desired. They have a collection of firemen, nearly all developed themselves or tweaked since arriving. They are Los Bomberos.