Yesterday, Mariners starting pitcher Luis Castillo battled through five scoreless innings against the Astros, before Seattle lost 2-1 in extras. This afternoon, Mariners starting pitcher Luis Castillo will face the Astros in his second-ever Major League start. This will also be his second time starting immediately after Luis Castillo.
Do not be confused and/or frightened: These are two separate Luis Castillos, who just happen to be starting pitchers for the same team, reliably pitching on back-to-back days due to their timing in the rotation. Somehow, this is not unprecedented: According to Daniel Kramer at MLB.com, Bobby Joseph Jones and Bobby Mitchell Jones pulled off the feat for the Mets, then did it again two years later for the Padres. The two Castillos have an easier run to match the record, since they're still on the same team. Depending on the performance of the second Luis Castillo this afternoon, they may well be on track to exceed it.
While this is more befuddling than the early-season furor surrounding Max Muncy the younger playing at the same time as Max Muncy the elder, it is not insurmountable. Databases like Baseball Savant and Baseball-Reference have maintained "Luis Castillo" for both pitchers, but the media has opted for the age-old strategy of chucking an initial in there. So let's clear it up here: Luis Miguel Castillo, 32, is the three-time All-Star who has become part of the Mariners' core. He is nicknamed "The Rock." Luis Felipe Castillo, 30, is a pitcher with only three previous Major League appearances before this season, all in relief with the Detroit Tigers in 2022. He was playing in the NPB before the Mariners signed him to a minor league contract in January, then made one start in Triple-A Tacoma before receiving his MLB call-up to fill out the rotation in George Kirby's absence. In recognition of his nominal kinship with Luis M. Castillo, he has been nicknamed "Pebble."
Aside from their completely different appearances, here's how to tell them apart: Luis M. Castillo's repertoire includes a four-seamer, sinker, slider, and change-up mix that he throws sidearm, at one of the most dramatic angles in the league. On the other hand, Luis F. Castillo has ... a four-seamer, sinker, slider, and change-up mix that he also throws sidearm, at one of the most dramatic angles in the league.
"We've had a lot of conversations, actually," Luis M. Castillo said, "because I saw him pitch and his arm angle is very similar to mine, and the way the ball moves, it's kind of identical to mine."
Perhaps Mariners executive Jerry Dipoto has determined the latest market inefficiency: signing pitchers with the same name, repertoire, and style of delivery and having them pitch on back-to-back days to confuse their opponents. Who can remember which Luis Castillo wears No. 58 on his jersey, and which one wears No. 43? No, the easiest way to distinguish the Luis Castillos is by their arm angle. According to Statcast, Luis M. Castillo throws at a 17-degree angle; Luis F. Castillo throws at a 14-degree angle. And there you have it. If his sinker has hitters in hell, it's Luis Miguel. If he pitches the following day, it's Luis Felipe.
