Mariners get closer Diego Castillo in trade with Rays for Chargois, prospect

Jul 29, 2021, 4:36 PM | Updated: 4:45 pm
Mariners RHP Diego Castillo...
New Mariners reliever Diego Castillo has 14 saves this year. (Getty)

Two days after trading top reliever Kendall Graveman to the Houston Astros, the Mariners have acquired his apparent replacement in the form of Diego Castillo, the closer of the Tampa Bay Rays.

Dipoto: Graveman deal had to happen when it did, ‘too good to pass up’

Reports of Seattle’s trade for the 27-year-old right hander surfaced on Twitter around 4 p.m. Thursday, with the Mariners officially announcing the deal shortly after.

Reliever JT Chargois and infield prospect Austin Shenton are the two players heading to the Rays in exchange for Castillo.

Castillo has 14 saves and a 2.72 ERA in 37 games this year for Tampa. Since making his MLB debut in 2018, he has a career 2.99 ERA and 26 saves in 167 games (183 1/3 innings). He also brings postseason experience to Seattle from his time with the Rays.

The hard-throwing Castillo ranks very well in the advanced metrics department. According to, his expected batting average (93rd percentile), expected ERA (98th percentile), expected slugging percentage (90th percentile), chase rate (95th percentile), strikeout rate (93rd percentile) and whiff rate (92nd percentile) are among the league’s best this year.

Additionally, Castillo is under club control through the 2024 season, giving the Mariners a young, high-leverage arm for the next few seasons. Fans and reportedly even some Mariners players were upset about the loss of Graveman from Tuesday’s trade, but Graveman is older (30) than Castillo and will be a free agent after this season.

As far as the players the Mariners lose in the move, Chargois has been a solid arm for Seattle’s impressive bullpen this season. The 30-year-old right-hander signed a minor league deal with the Mariners this past offseason and has a 3.00 ERA with 29 strikeouts to six walks in 30 innings this season.

Shenton is a local product, hailing from Bellingham and starring in junior college at Bellevue College. The Mariners drafted him in the fifth round of the 2019 MLB Draft. He was with Double-A Arkansas after starting the year in Single-A Everett, and between the two levels has a .300/.414/.566 slash line with 12 home runs and 61 RBIs in 67 games. Prior to the trade, Shenton was the Mariners’ No. 17-ranked prospect according to MLB Pipeline.

Follow Brandon Gustafson on Twitter.

More on the Mariners at the MLB trade deadline

O’Neil: Despite timing, Graveman trade kind of move M’s should be making
Drayer: Role M’s farm system depth could play at trade deadline
M’s Takeaways: Trade addition Abraham Toro’s strong first impression
Mariners trade prospects to Pirates for starter Tyler Anderson
Mariners send Graveman, Montero to Astros for Toro, Joe Smith
Mariners need another pitcher, so who should they target via trade?
M’s Trade Deadline: The Whit Merrifield rumor may have legs

See you next season

Chevrolet Silverado

Seattle Mariners

Mariners Semien Crawford...
Brent Stecker

Jerry Dipoto addresses how Mariners may find a fit in SS free-agency class

The Mariners have their shortstop, so why would they be interested in one of the big name free agent shortstops? Jerry Dipoto sheds some light.
14 hours ago
Mariners Mitch Haniger, Jarred Kelenic...
Brandon Gustafson

Is the future of the Mariners’ outfield as set as we thought?

The outfield is where the Mariners appeared to have the brightest future entering 2021, but the way the season played out changed some things.
5 days ago
Mariners Dodgers Chris Taylor...
Brent Stecker

The potential Mariners free agency targets to watch in MLB playoffs

A number of players set to enter free agency who could be interesting to the Mariners are still playing in the postseason. We break them down.
7 days ago
Mariners Mitch Haniger...
Brent Stecker

Heaps: Mitch Haniger’s Mariners article is worth getting fired up about

Jake Heaps of 710 ESPN Seattle's Jake and Stacy shares why Mitch Haniger's message from his column in The Players' Tribune makes him excited about the Mariners.
8 days ago
Mariners OF Julio Rodríguez...
Brandon Gustafson

Jerry Dipoto Show: Julio Rodríguez has opportunity to make Mariners, offseason priorities

During a visit with Mike Salk, Jerry Dipoto shared the Mariners' offseason focus and what the plan is with top prospect Julio Rodríguez .
8 days ago
Mariners Yankees Alfonso Soriano...
Dave Grosby

Groz Remembers 2001 Mariners: The magic runs out in the ALCS

The 2001 Mariners made it back to the ALCS for a rematch with the Yankees, but the dreams from their 116-win regular season were dashed.
9 days ago
Mariners get closer Diego Castillo in trade with Rays for Chargois, prospect