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The Red Report 2019 — Luis Castillo

Is this the year he becomes an ace?

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Cincinnati Reds Photo Day Photo by Rob Tringali/Getty Images

Fast Facts

  • Right-handed pitcher
  • 26 years old
  • Finished eighth in Rookie of the Year balloting in 2017
  • Better at baseball than you or any of your friends

Organizational history

  • Signed by the San Francisco Giants as an international free agent in 2011
  • Traded by the Giants with Kendry Flores to the Miami Marlins for Casey McGehee
  • Traded by the Marlins to the San Diego Padres in a six-player deal, then given back to Miami when Colin Rea’s medicals were called into question
  • Traded by the Marlins with Zeek White and Austin Brice to the Cincinnati Reds in exchange for Dan Straily
  • Will be arbitration-eligible after 2020, and a free agent after 2023

Career stats

Scouting report

Ken Gif-y Jr.

Luis is like

And then I’m like



In retrospect, it was always going to be difficult for Luis Castillo to finish the 2018 season having fully lived up to the potential his 2017 debut hinted at. The Cincinnati Reds hadn’t had a pitcher look the way he did in his rookie season in some time, as Castillo threw 89.1 innings with a 3.12 ERA, a 27.3 percent strikeout rate, and a 84 FIP-. His xwOBA allowed was in the 92nd percentile among among MLB pitchers, his fastball was Noah Syndergaard-esque, and his change-up was nightmare fuel for hitters. Lots of digital ink was used to declare Castillo an ace-in-waiting, with a breakout campaign in 2018 all that was needed to solidify him as one of the game’s most dominant young starters.

The breakout didn’t happen. Castillo finished April with a 7.85 ERA, with 24 strikeouts and 13 walks in 28.2 innings. Questions swirled about what was holding him back, and as’s Mark Sheldon wrote about at the time, everything from a changed arm angle to a dip in velocity to even tipping pitches was discussed as explanations for Castillo’s sudden struggles. He steadied himself a bit over the next couple of months, but when the All-Star break rolled around, his ERA was still sitting at 5.49, with 19 home runs allowed in 103.1 innings.

When the Reds returned for the second half of the season, however, Castillo pitched like a man who had figured things out. He owned a 2.44 ERA in 66.1 innings the rest of the way, with 69 strikeouts, 14 walks and nine homers allowed. He was at his best in the month of September, posting a 1.09 ERA in 33 innings with a dreamy line of 34 strikeouts, eight walks and four homers allowed.

Where does all of that leave Castillo and the Reds? Oddly enough, in a place very similar to where they were a year ago. Castillo didn’t achieve the breakout many envisioned in 2018, but because he finished the season with such a compelling run of performances, we’ve found ourselves once again optimistic that he’ll establish himself as a frontline starter this year.

For that to happen, Castillo will need to prove that the regression in both his batted ball profile and his overall stuff in 2018 was a mirage. His four-seam velocity dropped from 97.4 to 95.8, and lost a considerable amount of the spin it had when he first broke into the majors. Opponents’ average exit velocity also climbed from 84.9 to 88.1, and their xwOBA went from .264 to .318. It was a clear step back across the board, and if those are the kind of numbers he’s settled into, Castillo is much closer to a No. 4 than a No. 1.

What Castillo does still have going for him, though, is a fastball that remains near elite in terms of its velocity, and a change-up that might be one of the best pitches in the sport. He also throws tons of strikes, and still has plenty of projection in his slider. There’s a reason that, even after his disappointing 2018, The Athletic’s Eno Sarris essentially said Castillo is as close to a perfect prototype of a young pitcher as we have in today’s game.

If he doesn’t make the jump he seems capable of making, it will be another disappointment for an organization who has seen one arm after another fail to live up to their potential over the past five seasons. He’ll still settle in as a mid-to-back-end rotation cog, but it will mean the Reds’ search for an ace will need to continue in free agency — good luck with that — or in still-developing prospects like Tony Santillan and Hunter Greene.

If he does become an ace, though, then that doesn’t just make Cincinnati a dangerous team in the long-term — it makes the team a contender right now. The Reds, after all, were in trade talks earlier in the winter regarding Cleveland Indians ace Corey Kluber, with the idea that adding a No. 1 starter was the difference between the team merely playing meaningful games in September and the team actually making the postseason. If Castillo is a six-win kind of pitcher in 2019, and the trio of Sonny Gray, Alex Wood and Tanner Roark each perform in the roles they were brought in to fill, then the Reds’ playoff push becomes a very legitimate possibility.