The Twins have signed reliever Diego Castillo to a minor league contract. The former Rays and Mariners setup man was announced as part of the Opening Day roster for their Triple-A affiliate in St. Paul.
From 2018-22, the now-30-year-old Castillo was excellent out of the bullpens in Tampa Bay and Seattle, pitching to a combined 3.12 earned run average (3.69 FIP, 3.38 SIERA) with a strong 28.1% strikeout rate and an 8.9% walk rate that’s barely north of the league average. He kept the ball on the ground at an impressive 50.7% clip as well, and Castillo yielded just 1.07 long balls per nine frames.
Castillo has battled shoulder trouble throughout his career, however — three different IL stints — and that seems to have taken some toll on the righty. Early in his career, he averaged 98.8 mph on his four-seamer and 98.2 mph on his sinker. Those velocities were down to 94 mph with the Mariners in 2023. Castillo was rocked for six runs in his first 8 2/3 innings last season, walking an uncharacteristic seven of 41 hitters (17.1%) and plunking another during that time.
The Mariners passed Castillo and his $2.95MM salary through waivers unclaimed last May, surely hoping that he’d return to form in Triple-A Tacoma and help the club later in the season. However, his time in Tacoma didn’t go much better. In 47 1/3 frames, he posted a dreary 5.13 ERA with a decent 22.1% strikeout rate but also an alarming 15.5% walk rate. The Mariners never brought him back to the big leagues, and Castillo elected free agency at season’s end.
The Rangers signed Castillo to a minor league pact over the winter but weren’t able to get him straightened out in spring training. Command was once again a prominent issue. He walked six of 39 opponents with Texas (15.4%), plunked another and tossed a wild pitch.
Despite the sharp decline since the end of the 2022 season, Castillo has a strong overall track record in the big leagues. Minnesota, meanwhile, opened the season with closer Jhoan Duran (oblique strain) and relievers Caleb Thielbar (hamstring strain), Justin Topa (patellar tendinitis) and Josh Staumont (calf strain) on the injured list. It’s not a surprise to see them add a veteran arm with some big league success under his belt, but Castillo is clearly a project for them at this point.
If the Twins are able to get him back on track, Castillo’s 4.150 years of big league service time mean he can be controlled via arbitration through the 2025 season.
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