When it comes to sources of watchability, the Mariners certainly aren’t lacking. I could list the countless amount of exciting players they have on the roster, the consistent positive energy their home games produce, or Mariner Moose, but let’s just say that a game in Seattle is at the top of the pecking order in the “oooh I want to tune in to watch that” scale.

There’s another aspect of Mariners games that add to the entertainment value, however; their consistently down to the wire. No team won more one-run games in 2022 or 2021, and participating in those affairs provides the opportunity for high-intensity baseball at its finest. Somehow, someway, chaos is about to ensue, and you don’t want to miss out!

With higher leverage comes a greater need for a talented bullpen, and that’s not an issue in Seattle. Only the Dodgers bullpen allowed a lower expected weighted on-base average (xwOBA), and no team induced softer contact than them; they were also tied for first in Fangraphs’ pitching+ metric. Whatever way you slice it, when a Mariners reliever entered the game, manager Scott Servais had every reason to have faith that things would go smoothly.

Statistically, the results have still been strong this year, but the point of this piece was never to focus on the quality of Seattle’s bullpen – there’s not much to add in that regard. Rather, how they go about their craft is much more fascinating.

Think back to the first time you were taught to throw a baseball. Most likely, it involved a traditional over-the-top motion that you get right off a “how to throw a baseball correctly” Youtube video. The thing is, though, there is never a perfect model of mechanics for a hitter or pitcher to follow. Each individual is unique, and finding what’s comfortable generally is more beneficial than simply following the book.

Fortunately, it’s as if every Mariners reliever not only disregarded the book, but lit it on fire. There’s unconventional, and then there’s the 2023 Seattle bullpen.

To summarize:

• They have the lowest vertical point of any team in the MLB
• On average, their pitchers release the ball further to the right side than any team
• Only two other teams have less arm-side movement than them
• They locate to the right side of the plate more than any team

There’s a lot going on here! Mainly, though, what you need to know is the Mariners bring as much funk as possible, and do it from the lowest possible angle. Speaking of which, do consider that they do not have a single reliever with an average release height at or above the league average (5.71 ft). How is that even possible? Clearly, they have a type, and it becomes clearer when we look at every reliever Seattle has used this year. While they may start from the bottom, we’ll work from the highest release point on down.

First up? A reliever whose path to the Mariners differs slightly from the rest. See, for the most part, Seattle’s bullpen consists of players acquired either on minor-league deals, waiver claims, or as the return for them trading away a well-known player. Diego Castillo, on the other hand, was the well-known player in a midseason trade with the Rays, and it’s pretty easy to see why.

Castillo’s release height (5.63 ft) is very close to the league average, though it’s still on the lower side, and what he brings to the table represents another grand theme with the Mariners’ relief corps – they love to sweep it. No bullpen throws more sliders than they do, and Castillo embodies that by throwing his 63.3% of the time last year. I mean, when you can do this, who wouldn’t want to throw their slider as often as possible?

Between 2021 and 2022, Castillo’s slider produced a run value of negative 22, while its pitch model-based metrics (122 stuff+) were well above the league average last year. Those numbers are notably worse this year, but it’s only a matter of time before his performance slides back to where it was previously. See what I did there?

Now, for the southpaws! What’s so beautiful about being a relief pitcher is that, unlike other positions, the trajectory is never linear; sometimes, a diamond in the rough is awaiting to be revealed. Well, that may very well be the case for a few of Seattle’s relievers, chief among them lefty Gabe Speier. In the most bizarre season imaginable, the former 19th-round pick posted a 2.76 expected ERA over 19.1 innings in the majors in 2022, only to allow a 14.51 ERA and 8.01 FIP in 26.2 Triple-A innings. The Triple-A struggles were enough for the Royals to part ways with him following the year, only for Seattle to claim him off waivers a month later.

Well, let’s just say things couldn’t be going better. In addition to not allowing an earned run over his first 10.1 innings, Speier’s underlying metrics (2.03 xERA, 2.08 FIP) are off the charts, and it comes down to the same sinker-slider pairing that is a trademark of this relief corps. Here’s the sinker, currently inducing a ground ball on 76.5%(!) of the batted balls against it:

The 19.3 inches of horizontal movement Speier gets from his sinker is an exceptional 3.3 inches above the league average playing a huge role in him limiting damage at the level he does. Of course, it also helps when you can pair it with a bat-missing slider like this:

In addition to this impressive two-pitch mix, Speier also has a plan of attack that symbolizes Seattle’s bullpen – he’s not afraid to go after opposing hitters. In fact, their bullpen currently throws more pitches in the zone than any other team, continuing in on with their remarkable distinctiveness. With the ability to miss barrels, not walk batters, and generate more whiffs than expected, he’ll continue to use his sink to swim.

Outside of Speier, the Mariners have called upon lefty relievers sparingly, with Tayler Saucedo the only other southpaw to appear in a game this year. It’s only been two innings, but one look at the horizontal nature of his sinker-changeup pairing makes it quite clear why Seattle targeted him this offseason:

Righties, don’t fret; the rest of this piece is dedicated to them! Unlike Speier and Saucedo, it took more than a waiver claim for the Mariners to acquire Trevor Gott, who signed a major-league deal with them this offseason. Still, considering how effective (2.94 xERA) he was for the Brewers in 2022, it’s a bit strange he was not tendered a contract by them, though, sometimes, things happen for a reason.

With Seattle, Gott has continued to flourish (13 IP, 2.5 xERA, 2.12 FIP), and continues to use his low release height (5.31 ft) to his advantage, using a cutter-sinker-fastball trio that is an absolute marvel:

Why decide between one fastball variation when you can do it all? Regardless, it’s going to be starting from the bottom, and baffling hitters from there.

Both Jose Rodriguez and JB Bukauskas have only pitched in one game for Seattle, but each follow the same characteristics (low release height) that defines this bullpen. Rodriguez is back in Triple-A while Bukauskas is now with the Brewers, though one visual look at each screams “Mariners” more than life itself:

Here’s to more opportunities ahead for both of them! In the meantime, tuning into a Mariners game has more often than not meant being treating to the Matt Brash experience, which is a time of utter joy. If there was a time for you to question how any player every makes contact with a pitch, it’s with Brash on the mound. I’ll let the video speak for itself:

My friends, I am absolutely speechless. Brash is throwing his slider over half of time, and it’s missing bats on 57.1% of the swings against it. All told, he has used it to strike out 42.3% of the 52 batters he’s faced thus far, and does so in typical Mariners fashion – low release height (5.17 ft), absurd horizontal break. If we all ask the MLB app to set up Matt Brash alerts, do you think that would work? I, for one, couldn’t think of one matter more pressing than that!

Just when you thought this bullpen couldn’t get more fun, the American League leader in skill interactive ERA (SIERA) and expected ERA has pitched a grand total of 3.1 innings for them! Want to know how Seattle has constructed such a vaunted relief corps? Acquiring both Brash and Andres Munoz from the Padres in a span of a few weeks in 2020 is a great place to start. Speaking of which, let’s not bury the lead anymore:

What if you took the underlying characteristics the Mariners seem to prioritize and put it on steroids? That’s how you end up with Munoz, who throws from a very low release height (5.12 ft) to go along with a dominant horizontal sinker-slider pairing. Velocity isn’t a strength for this bullpen, but it doesn’t hurt when you can simply have it all. Can’t decide whether you want peanut butter (underlying characteristics) or chocolate (velocity)? Think of Munoz as the Reese’s’ Cups of this bullpen. Who doesn’t love Reese’s?

At the same release height as Munoz but with an average fastball over 12 MPH less is Darren McCaughan, who has been a starter in the minors and has only pitched one inning with Seattle, but he would appear to fit perfectly in their bullpen. Here’s why:

That sweeping slider impressed Fangraphs’ stuff+ model (119) in the very brief sample size, and with a track record of limiting walks, he’ll hopefully find his way back up to Seattle very shortly. After all, as Justin Topa has demonstrated, the path forward is rarely linear in baseball. A 17th round pick in 2013, Topa had to play in a Canadian independent league in 2017 and didn’t make his MLB debut until his age-29 season in 2020; even then, he only threw 18.1 innings in three seasons for the Brewers before being traded to the Mariners this past offseason.

Now, Topa has commonly found himself pitching in the 8th inning or later for Seattle, a dramatic turn of events. Then again, when you’ve allowed zero barrels and just one fly ball (!) over your first 10 innings, you’re going to earn the trust of the team very quickly. Wouldn’t you know; he’s dropped three inches of vertical drop on his slider, turning it into a purely horizontal sweeper to pair with worm-burning sinker.

Do I need to repeat myself again? In many ways, Topa’s unique profile, in addition to his bumpy journey to this point, makes him one of the poster children of this bullpen. Hopefully, the worms take cover during the late innings.

How strong is the Mariners bullpen? Matt Festa, who was tied for 45th a year ago among relievers with 50+ innings pitched in skill interactive ERA (SIERA), is currently in Triple-A, an unfortunate turn of events for the 30-year-old. Based on his accomplishments last season, it’s hard to imagine he’s long for the minors, particularly with a fastball-sweeper mix coming from a release point that screams “MARINERS”. As you’ll see, the all caps was intentional:

Told you!

Now, to the final two, who aren’t only representations of this bullpen as a whole, but also amongst the game’s most unique pitchers. Both are in the bottom-15 among relievers in release height this season, yet could not be more different. Again, there are several ways to get outs.

Generally, a reliever striking out 34.7% of the batters he’s faced since the start of 2021 would be expected to be like Andres Munoz, topping triple-digits with ease. Instead, Paul Sewald’s 92 MPH fastball wouldn’t appear to present any sort of fear at first glance. Well, that’s where starting from the bottom comes in handy:

Did I mention he has a sweeper as well?

The poster child of Seattle’s bullpen, Sewald came to the Mariners after being non-tendered by the Mets prior to the 2021 season. Now, he’s statistically been one of the most dominant relievers in baseball, doing so in spite of elite velocity due to underlying pitch characteristics. How can you not be romantic about baseball, particularly relief pitchers?

In case you weren’t aware, the MLB Draft only consists of 20 rounds now, meaning less opportunities for pitchers such as Penn Murfee. A 33rd-round pick in 2018, Murfee fails to average 90 MPH with his fastball, yet sports a 2.79 ERA dating back to last year. I could get into more specifics, but just answer this question: does this look fun to hit?

Yep, that’s what I thought. If you can present enough deception that hitters simply cannot square you up – Murfee ranks in the 97th percentile in hard hit% starting in 2021 – then how hard you throw matters much less. If everyone threw 100 MPH, where would the fun be? For every Andres Munoz, having a Penn Murfee in the same bullpen presents the sort of redundancy that allows for each individual to stand out on their own. Some people like to eat the same cereal every day, but why do that that you can have Cinnamon Toast Crunch, Captain Crunch, AND Apple Jacks? The cinnamon, the caramel, the apple; it’s all there for you pending an open mind.

Now, this article is by no means an analysis of the effectiveness of Seattle’s bullpen strategy. Ultimately, the goal of pitchers is to get outs by any means necessary, and that happens in many ways. Really, this is a way of showing how many different strategies there are to skin a cat, and how entertaining the Mariners’ relief corps is. “Started from the bottom” can be seen as a description of their release height, but almost all of these relievers have had turbulent rides to their current situation. A symbolism of the saying “don’t judge by a book by its cover”, don’t let the velo readings fool you, this bullpen is here to steal the spotlight.