The Mariners righty could be on the trade market.
The Seattle Mariners have a plethora of rotation arms. I see a mock trade proposal for Bryan Woo or Bryce Miller almost daily. Unfortunately, those (and all) hypothetical trades are futile suggestions due to the Mariners’ financial situation. Seattle reportedly only has about $15-20 million to spend this offseason. They’re not rebuilding, but rather in a perpetual quest to win 54% of their games. Trading cheap, controllable major league pitchers is counterproductive to that pursuit, meaning they likely won’t be trading any of their arbitration-eligible pitchers. Luis Castillo is owed about $24MM in each of the next three seasons. The Mariners have a pitching surplus and desire to improve their lineup on a limited budget. To me, that sounds like a perfect trade partner.
The Smash Case: He’s been good
Luis Castillo has been in the league for eight seasons, has thrown 1200 innings, and has a 3.56 ERA. Excluding his debut season and the shortened 2020 season, he’s made at least 25 starts every year. Oh, and Pedro Martinez helped him with his changeup.
While he’s past his prime, he’s still a very productive pitcher. In 175 innings, he ran a 3.64 ERA along with a 1.17 WHIP. He struck out 24.3% of hitters while walking just 6.5%. In terms of arsenal, he primarily uses a four-seam fastball while mixing in a sinker, slider, and changeup.
The four-seam comes in at about 95 MPH and appears flat due to Castillo’s very low release point. Castillo consistently locates it at the top of the zone where it performs best. It’s worth noting that Castillo hardly extends down the mound at all, leading to the lowest extension in all of baseball, so that 95 probably feels closer to 93. He uses his sinker as any righty should, jamming same-handed hitters inside. The slider is a “gyro slider”, meaning that the spin doesn’t translate to pitch movement and the ball appears to stay straight. It may sound like a bad thing, but it’s deceptive to the hitter’s eye. Castillo uses the slider in the zone against lefties for called strikes and out of the zone against righties for whiffs.
Lastly, there’s the changeup I mentioned earlier. At one time, it was one of the best pitches in baseball, but Castillo has gone away from it in recent years. It currently only represents 14% of his pitches, almost exclusively used against lefties. For whatever reason, the pitch isn’t the weapon it used to be, despite similar movement and locations. Hitters just aren’t whiffing as often. It’s still a solid pitch and a nice weapon to have in the arsenal, but it’s not the dominant offspeed pitch it once was.
The Pass Case: He’s getting worse
You: “I’m only 35, I have my whole life ahead of me.”
Sports Broadcaster: “Here comes the oldest player in the league. He’s 32. A miracle.”
— Troy Johnson (@_troyjohnson) May 19, 2024
Castillo has a well-rounded arsenal with pitches to throw against both sides of the plate. He gets ground balls, strikes out hitters, and limits free passes. The metrics on his individual pitches are solid, and he rarely ever misses time. What’s not to like?
Well, while the stats are positive, they’re almost all headed in the wrong direction. His strikeout rate fell from 27.3% to 24.3%. His fastball lost some velocity, and the swinging strike rate with it fell considerably. For the past several years, he’s been able to overpower lineups with his fastball. The velocity dip could be no more than a down year, but it’s more likely a sign of things to come. At 95 MPH, he was able to ride the pitch to a solid year. If the velocity continues to drop, it may be tough sledding for Castillo.
It’s worth noting Castillo threw his fastball 45% of the time last season. The Red Sox throw fewer fastballs than anyone. Castillo, in his gyro slider, has a platoon-neutral pitch he can throw for strikes. There may be an opportunity to decrease his fastball usage in favor of more sliders to help mask the velocity decline.
The Verdict: Pass
Castillo is only 31 years old. There may be plenty left in the tank. If he were on a one-year contract, this would be an easy smash for me. Unfortunately, you’re trading for three years of Castillo. His arm angle fell, and he lost a touch of velocity last year. Maybe the right pitching coach can help him return to form and provide three more ace-level seasons. Personally, I think 2024 was a sign of things to come, and committing to Castillo for three seasons would be a mistake.