Boston Red Sox Claim Kansas City Royals Pitcher Off the Waiver Wire

Castillo made his big league debut in 2022, posting a 3.05 ERA and 0.968 WHIP in nine outings with the Blue Jays. After getting traded to the Royals, however, Castillo went 0-2 with a 1.768 WHIP as a back-end starter.

The Royals used Castillo as a long reliever in 2023, first activating the righty in May.

Castillo was firing on all cylinders through his first three appearances of the season, boasting a 2.89 ERA in 9.1 innings to that point. After getting rocked by the Chicago White Sox on May 21, however, Castillo was optioned to Triple-A.

Following one MLB outing in July and two more in August, Castillo ended 2023 with an 0-1 record, 4.43 ERA and 1.426 WHIP.

The Red Sox may have just traded longtime ace Chris Sale to the Atlanta Braves, muddying the waters on their starting rotation, but they still have enough options to keep Castillo coming out of the bullpen. The 24-year-old also has one option remaining, meaning Boston doesn't necessarily have to keep Castillo on the major league roster for all of 2024.