Mariners acquire reliever Diego Castillo from Rays for J.T. Chargois and prospect Austin Shenton

Is Jerry done? Time will tell! Meanwhile, here’s a really good reliever!

Hi, folks! Eric here, hitting you with the breaking news. After a long day of impatiently refreshing their timelines and checking notifications, Mariners fans have something to chew on. Jerry Dipoto strikes again with another deadline deal that brings one of the better relievers in the AL to Seattle from our favorite trade partner, the Tampa Bay Rays.

Jeff Passan had it first, naturally:

Then the return came through.

Okay! Chargois was picked off the scrap heap and pitched pretty well out of bullpen, but not a huge loss nor is he irreplaceable. Shenton hurts a little bit, mostly for his potential bat and also his “Local Boy Makes Good” status as a Bellingham native, but as I’ve been reminded by other staffers, his glove seems unlikely to stick at third base and so he didn’t really have a position if he made the team in the next 2 to 3 seasons.

Here’s a good way to look at the deal, if you’re so inclined:

The headliner of this deal is, pretty obviously, Castillo. He’s yet another example of the Rays’ player development Death Star, signed back in 2014 for just $64,000 out of the DR. A reliever since day one in the system, Castillo excelled in every single level of the minors before debuting in 2018. Since that debut, he’s been simply excellent, with a 3.58 career FIP; this season, he’s taken the lion’s share of closing duties for the Rays, picking up 14 saves and striking out 12.1 batters/9. I mean, this looks pretty nasty:

Even better, Castillo is far from a rental. He should be entering his first arbitration year in 2022, meaning the M’s will have his rights for three cost-controlled seasons, and he’s just 27 this season. The combination of Castillo, Ken Giles, Andres Muñoz, and Paul Sewald (??) could be a dangerous quartet for years to come.

Why, then, would the Rays trade him away? Putting aside the rhetorical question of “why would a contending team trade its closer to another contender?” — which sounds familiar even to short-time readers of this blog — it boils down to some combination of the following three reasons:

1. The Rays have an inexplicably strong belief in J.T. Chargois, and despite the fact that two different organizations have given up on him, they believe the 30-year-old’s breakout 2021 is far from a fluke.
2. As a notoriously cheap organization, Tampa is concerned about Castillo’s arbitration expectations in 2022 and beyond.
3. The Rays might think Austin Shenton, who has torn up Everett and Arkansas this season, has a chance to be special.

As you can likely tell from above, I don’t particularly think reason #1 is true; relievers are notoriously volatile, and while Mikey did a great job writing up JT earlier this season, I’m still not sold on his long-term viability. Reason #2 likely has some impact on the trade logic here, although Castillo will only command a few million dollars at best in his first year of arb, since those discussions have historically centered around “old-school” stats like saves.

That leaves Reason #3, and it seems clear that the Mariners have questions about Shenton’s ability to stick at third. Regardless, he was certainly not going to help the club contend this season, and the Mariners’ vaunted ~financial flexibility~ should allow them to add a big-money bopper this offseason. If that player slots in at third, or elsewhere in the infield, Shenton may have been squeezed out of a position regardless.

All this is to say, a few years from now, we might be looking back at this and regretting giving up on a red-hot hitting prospect like Shenton. But Castillo is a very strong bullpen arm and is a much safer bet to contribute to the 2022 Mariners and beyond than a guy like Chargois. The final lingering question: What else does Jerry Dipoto have up his sleeve?