MLB expert highlights an unexpected Mariners strength post-trade deadline

While there's no getting around the fact the Seattle Mariners have only made the playoffs once this decade (and indeed since 2001), you also have to accept they have been consistent in remaining in contention. While statistics can often be manipulated to support any argument, it's still impressive that they are one of only five teams to win at least 85 games in each of the past four seasons.

There are any number of reasons why this has been possible, but one has to include the Mariners bullpen. Here's a look at the team rankings in the majors by the M's relievers since 2021, and how this compares to what they have done so far this year:

As per the above table, this season has been a mixed bag for the relievers, with the Mariners often leaning on the trio of Andrés Muñoz, Matt Brash, and Gabe Speier. There have been few other consistent options in the bullpen, although it seems good times are coming in Seattle, at least according to one MLB expert.

Mariners predicted to have the best bullpen in baseball

Eno Sarris of The Athletic (subscription required) has published an intriguing article which poses the question: Which team has the best bullpen in baseball for the rest of the season?

He includes the likes of the New York Yankees, New York Mets, and San Diego Padres, but lo and behold, ends up predicting that the Mariners will have the best bullpen in MLB moving forward in 2025.

We'll confess we were slightly shocked by this turn of events. And in fairness, even Sarris calls it a surprise result, but we're more than happy to accept the findings of someone who knows his stuff when it comes to pitching.

For some context and more understanding, here's a breakdown of the methodology which he applied:

Using OOPSY projections on FanGraphs which incorporates ERA, K%, BB%, Stuff+ and Location+, and only for each team's top five relievers, to compare only the “A” bullpens to show the best bullpens in baseball going forward sorted by ERA.

Sarris does give Muñoz and Brash their due as elite elite relievers, while also offering kudos to the underrated Speier and the recently acquired Caleb Ferguson. However, there are a couple of qualifiers to consider in all of this. (In the interest of objectivity, you do understand.)

First is that the Mariners' top-ranked ERA of 2.96 moving forward is helped by playing in T-Mobile Park, which is the top pitchers’ park in baseball according to Statcast park factors. The second qualifier is that if Sarris had instead ranked the bullpens by WAR, the M's would have actually finished third behind the Padres and Mets.

While we're on the subject of qualifiers, we'll add in a minor one ourselves of Sarris only considering the top five relievers on each team. Like it or not — at least until the playoffs anyway — this is a team game where you can't just solely rely on your five best bullpen arms no matter how good they are, meaning the Mariners still have to use certain players at times.

One example of the unreliability elsewhere was Trent Thornton, who produced a 7.71 ERA in his first 18 appearances this year, but then recorded a 2.28 ERA in his 15 subsequent outings prior to his season-ending torn left Achilles. On the flip side Casey Legumina had a respectable 3.31 ERA in 31 games up to the end of June, but since then has seen this jump astronomically to a horrific 12.21 ERA in his 11 most recent appearances.

In summary, though, there's still enough reason to be optimistic about Sarris' conclusion, with the Mariners indeed looking in decent shape despite losing Thornton and not acquiring the high-leverage reliever they wanted. Ferguson is definitely a fine addition from the Pittsburgh Pirates and despite the grief we have given the bullpen at times this season, they are still ranked eighth in ERA.