40 in 25: Diego Castillo

[Ed. note: Please welcome the first of the new writers we’ll be introducing over the next couple of weeks, Bren Everfolly! They live in southern Idaho currently, so we’re excited to, much like the Mariners, continue to extend our tentacLLes all throughout the Great Northwest. You can follow them @everfolly on Twitter. Welcome, Bren!]

Although pragmatic phrases are anything but flashy, they appeal to the realist inside of us and help us avoid leaning too far into extremes. A favorite of mine is “hope for the best, plan for the worst”: the former, a cornerstone of the Seattle Mariners franchise throughout its history; the latter, an unfortunately frequent necessity. In the upcoming season, the Mariners have a bullpen that is well suited for both hope and fear, ceiling and floor. With all the talent in hand, for some it might be easy to overlook Diego Castillo. They shouldn’t.

Castillo is almost certainly a better reliever than he’s thought of by the average Mariners fan. This is, in part, due to the circumstances of his arrival to the roster: a recent fan and clubhouse favorite reliever had just been traded after a thrilling comeback win, and the dominating narrative was the perceived apathy of the team’s leadership. Of course, it was two days later that the deal that acquired Castillo to fill that void took place, but the moment was soured before it began. The cost to get him wasn’t steep, which when coupled with the fact that the Rays were in contention, lent itself to a narrative that maybe something was broken with him. In a little less than a month after arriving, his stat line wasn’t sweeping anybody off their feet.

FanGraphs

While his BABIP against and LOB% were satisfactory, his FIP and K-BB% were underwhelming, to say the least, and he was bitten hard by home runs in this stretch. Then after only appearing in 10 games, he was placed on the 10-day IL on August 20th. The whole sequence of events felt like one gut punch after another. If you only hope for the best, you sometimes find yourself disappointed. The naysayers of both trades were having their moment, and it seemed at the time the concerns about his dropping velocity over the last few years may have been foreshadowing for decline in other areas as well. The actual full scope of the situation is of course much more complicated, and you can find a wonderfully detailed breakdown of it all by LL’s own Michael Ajeto here.

As hard as that period of time was on fans, I cannot be convinced that it was harder for anyone but Castillo. Being traded from a true contender to a team riding on waves of chaos and luck can be fun if you let it, but the atmosphere from recent drama was indeed dire; an unenviable time to be a newcomer to that clubhouse.

However, Diego faced his struggles like a man with a plan. Coming back from the 10-day IL for the final month of play, he trailed only Casey Sadler and his scoreless streak for the best team ERA with 10+ innings.

FanGraphs

Over that time, he was fourth in Seattle’s relief corps in FIP at 3.09, and although he was middle of the pack with a BABIP against at .310, that was balanced with a very healthy 89.3 LOB%. Where he really shined, though, was in his K-BB%, leading all M’s relievers in that time at 30.8%. Of course it’s smart to shy away from small sample sizes, but he finished the year having posted career best numbers in K% (32.2) and BB% (7.3) for an overall K-BB% at 24.9% which ranked 14th best in MLB among qualifying relievers for the 2021 season.

Personally speaking, statistics only make up one side of the story of a player. It absolutely is important that a player be good, but that is only one element in calculating any individual’s impact on fun differential. The good news is Castillo has that in spades. Adrianne Leary wrote about the joy that exudes from him when he first came to Seattle, but it bears repeating. When he is at his best, the only thing the opposing batter can hope for is not to look absolutely foolish, like Hunter Renfroe chasing the slider here.

Who among us can do anything but smile remembering last Sept. 8th against the Astros, when he bounced back from a leadoff Correa single to strike out the next three batters to end the 8th inning, perfectly setting the tone for a 4 run rally that broke a tie and secured an 8-5 victory? If the Mariners hope to succeed in the AL West this year or beyond, we will need someone capable of felling titans with that level of efficiency.

There is a certain swagger and assuredness in his delivery that gives me a vague impression of Fernando Rodney, in the best possible way. When Castillo’s arrow misses the mark, though, it is with the purpose of fooling batters - which it usually does. In a year with young guys looking to prove themselves and players returning from injury, I expect he will be one of the team’s most consistent contributors. Diego Castillo brings both an energy and an arsenal that speak to a fan that harbors a genuine love for the game, and if he continues his performance from the end of last season, he is sure to be a key piece to Seattle’s late inning success - giving them his best, and making opposing hitters look their worst.