Mariners add All-Star starter Luis Castillo from Reds, send 4 prospects to Cincinnati

Mariners general manager Jerry Dipoto and Seattle’s front office made perhaps the biggest splash to date in this year’s pre-deadline trading market Friday evening, acquiring two-time All-Star starting pitcher Luis Castillo from the Reds in exchange for four prospects.

ESPN’s Jeff Passan first broke the news on Twitter, and MLB.com’s Mark Feinsand shared details of the transaction soon after.

Seattle later announced details of the deal, including a tweet with the statement: “Adding another ace.”

Over a dozen teams “made their bid” for Castillo leading up to Friday’s deal, but Seattle offered Cincinnati the best package prior to the Aug. 2 trade deadline, Feinsand said.

Castillo has started 14 games for the Reds this season, posting a 4-4 record and career-best 2.86 ERA. He has struck out 90 and walked 28 across 85 innings.

He last pitched Wednesday against the Marlins, meaning if he continues on normal rest when joining Seattle’s rotation, he could make his first start for the Mariners as early as next week’s series against the Yankees in New York.

“We see Luis Castillo as an impact, top of the rotation starter who’s currently on top of his game,” Dipoto said in a team release. “Our goal remains to play in the postseason, now and in the years to come. We believe adding Luis is a big step in that direction.”

Castillo debuted with Cincinnati in 2017, and has started 137 games with the club the past six seasons, compiling a 44-53 career record and 3.62 ERA with 860 strikeouts to 287 walks in 792 1/3 innings.

“He’s one of the best pitchers in the game,” Mariners manager Scott Servais told reporters in Houston postgame Friday. “Really established himself as a dominant starter in the National League.

“Certainly our guys, we’ve got a couple of his former teammates that are with us, so they know him very well and speak very highly about his stuff, his competitiveness and I think a few of them may have already been on the phone with him.”

His contract lasts through 2023, meaning the Mariners get Castillo for, potentially, two postseason races before the 29-year-old hits free agency in 2024.

He’ll receive an ace’s ransom of innings with the Mariners, but it’s unknown whether Seattle will cut innings from another starter or simply add Castillo to a six-man rotation. Seattle pitchers own a team ERA of 3.65 this season, good for fourth in the American League and seventh in baseball.

Seattle infielder Eugenio Suarez was traded by the Reds to the Mariners alongside outfielder Jesse Winker on March 14. When Suarez heard the news after Friday night’s loss that Castillo, a former teammate, was headed to Seattle, he said the two-time All-Star was one of the greatest teammates he’s ever had.

“Good guy. Good person,” Suarez said to his teammates, describing Castillo. “He’s one of the best pitchers in the game right now. I was so happy. I told everybody that they’re going to love him.”

Suarez called Castillo, who was happy to hear news of the trade. “(Castillo) just wants to compete. He just wants to win,” Suarez told ROOT Sports. “He throws hard. He’s got a good changeup, one of the best in the league.”

Castillo’s changeup was voted by managers, scouts, and executives as the best in the National League per Baseball America in both 2019 and 2021.

The Reds put a hefty price tag on a year and a half of Castillo’s services, but Dipoto accepted the blockbuster details. The Mariners will send four prospects — infielders Noelvi Marte and Edwin Arroyo and right-handers Levi Stoudt and Andrew Moore — to the Reds in return.

Marte, Arroyo and Stoudt are all among the top five prospects in Seattle’s system, per MLB Pipeline.

Marte, currently with High-A Everett, is considered the Mariners’ top prospect by MLB.com, as well as the No. 18 prospect in baseball this season.

The 20-year-old shortstop has posted a .281/.365/.473 career slash line in 256 games in the minors since signing with the Mariners in 2018.

This season, he is hitting .270/.360/.460 with 61 runs scored, 19 doubles, 15 home runs, 55 RBI and 12 stolen bases through 84 games.

Arroyo is Seattle’s No. 3 prospect and No. 93 in baseball. The 18-year-old was a second-round draft pick by Seattle in 2021, and is hitting .316/.385/.514 with 76 runs scored, 19 doubles, seven triples, 13 homers, 67 RBI and 21 stolen bases with Low-A Modesto this season through 87 games.

Stoudt, a third-round pick by Seattle in 2019, is considered the No. 5 prospect in the organization. The 24-year-old starter is 6-6 with a 5.28 ERA in 18 appearances with Double-A Arkansas this summer, and has struck out 82 while walking 22 across 87 innings.

Moore was selected by the Mariners in the 14th round in 2021. The 22-year-old reliever has a 2-1 record and 1.95 ERA with Modesto in 25 appearances this season.

When Winker heard the news of the Castillo trade, Seattle was down 10-1 in an eventual 11-1 thrashing by the Astros at Minute Maid Park in Houston. But landing a pitcher of Castillo’s caliber pumped Winker up, he admitted.

“On a day like today when you lose, and you come back in and get great news like that, you just move on from this one even quicker than we were going to anyway,” he said. “It’s an exciting time, for sure. ... He’s going to help big-time.

“He’s elite. That’s the easiest way to describe him. ... It’s good for the city of Seattle. They should be excited.”

Staff writer Lauren Smith contributed to this report.