Mariners acquire Diego Castillo from Rays

The Mariners added a powerful arm to their bullpen on Thursday night, acquiring right-hander Diego Castillo in exchange for righty reliever JT Chargois and minor league infielder baseman Austin Shenton.

Castillo, 27, was a key piece of the pennant-winning Rays’ bullpen last season and has continued to thrive in 2021, posting a 2.72 ERA with a 0.99 WHIP, 49 strikeouts, and 10 walks in 36.1 innings. His velocity has dropped a bit this season, but he still has the stuff to consistently overpower hitters, throwing a four-seamer that averages 95.5 MPH and a sinker that averages 94.8 MPH.

Castillo’s numbers this season aren’t as good as Graveman’s — the 30-year-old closer had an 0.82 ERA and 0.70 WHIP in Seattle — but he has better stuff, is younger, cheaper (he’s making $561,500 this season), and is under club control for far longer. Castillo is arbitration eligible through the 2024 season, while Graveman is a free agent at the end of this season.

After sitting out the 2020 season, the 30-year-old Chargois has bounced back in 2021 and will probably be a good get for Tampa. In 31 games, the righty has a 3.00 ERA with a 0.97 WHIP, 29 strikeouts, and just six walks in 30.0 frames.

Shenton, the Mariners’ fifth-round pick in 2019, has had a very good first full professional season, hitting .300/.414/.566 with 12 homers between High-A Everett and Double-A Arkansas while seeing time at first base, second base, and third base.