Amid a historically anemic start for the Cincinnati Reds offense, Reds fans have taken solace in Luis Castillo. The young flamethrower has been excellent to open the 2019 season (stats through his last start in San Diego): 30 IP, 13 H, 14 BB, 41 K, 308 ERA+.

We’ll quibble for a moment; the hits will start dropping in before long and that walk rate is rough, but Castillo is racking up the strikeouts and the stuff — always tantalizing — is definitely for real. I’m not convinced he’s suddenly a top-10 starter, but he might be top-20. That is quite a positive development.

A fancy stat to keep an eye on? Last year, the average exit velocity off his four-seam fastball was 90.6 (right around league average). This year? Down to 81.9. Is that drop for real? Permanent? I doubt it, but if it settles in the mid to upper 80s, that’ll mean the fastball is playing better. Despite the impressive velocity, Castillo’s fastball wasn’t even a good pitch in 2018. The xwOBA (read it like an on-base percentage) was .402; the pitch value by Fangraphs was -9.6. Not great. This year both numbers look quite a bit better.

I don’t think he’s suddenly solved all his fastball issues, but I do think he’s learning. Don’t misread me: Castillo’s been incredibly fortunate so far (.197 BABIP, 87.4 strand rate), but he’s also developing. Two things can be true at the same time. I wrote about the righty last winter, wondering if he’d be able to make a few tweaks to unlock the elite hurler within himself. As fraught with peril as a 30 inning sample can be, there’s reason to be confident.

Let’s enjoy Castillo’s first inning against the San Diego Padres.

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I love this. How cool would it be to see Luis Castillo and Fernando Tatis Jr. square off in the NLCS? Young star vs younger star. The Reds hurler starts the Padres shortstop off with a fastball down and away for ball one.

Castillo misses with a second fastball, belt-high and away.

Tatis, already with a handful of homers on the season (all of them off fastballs), can’t be taken lightly in a 2-0 count. Castillo can’t just serve up a fastball here; he splits the difference by nipping the inside corner with 96 MPH. Love the run on this pitch — and note how Tatis turns as it crosses the plate.

Still behind in the count at 2-1, Castillo busts out his true weapon, his changeup. This one is a beauty, running arm side and down, grabbing the inside corner for a called strike two. Through this very start in San Diego, hitters have managed a meager .083 batting average off it. I can see why.

It’s 2-2. Tatis has now paid witness to three fastballs (two away for balls, one inside for a strike) and a nasty change down and in for a strike. From the pitcher’s perspective, the appealing option is to bury the changeup further down and force the young shortstop to chase.

Castillo does just that, and the results are spectacular. That’s an absolutely tremendous changeup, well sequenced and perfectly located. Credit to Castillo for battling out of a 2-0 hole against a hitter with pop and punctuating it with the punchout.

Who doesn’t love a slow-motion look at a K?

Up next is Francisco Mejia. He’s greeted with a bicep-high fastball that runs out over the plate for ball one. Imagine how pleasant it must be to think, for just the hint of a second, that a Luis Castillo fastball is about to explode into your elbow. Pleasant indeed. It’s 1-0.

Mejia watches a changeup run off the plate away for ball two, and yet again the young Reds righty is behind in the count. He’s started exactly half of his exchanges with a first-pitch strike, hardly a dominant number (league average is 60.3%). As announcer Chris Welsh pointed out, Castillo has the stuff to mitigate the mistake, but great pitchers don’t do this. It’s something to work on.

Castillo runs a fastball right over the heart of the dish and Mejia sprays it foul. Not a great spot at all, but Castillo got away with it. You can see catcher Tucker Barnhart sat up low and away.

Castillo misses well out of the zone with another fastball, running the count to 3-1. As stated in the intro, walks are a blinking red light of a problem for Castillo, easily my biggest fear for him as he tries to emerge as an ace. Free passes are killers against Major League offenses, regardless of how good the hurler might be otherwise. I think he can work on it, though, but it remains a concern.

The fifth pitch of the at-bat is another fastball low and away. Mejia bounces it slowly to short and Jose Iglesias isn’t able to make a play. A rough sequence of pitches for Castillo results in a 1-out baserunner with a superstar coming to the plate.

Manny Machado’s Homer-like free agent odyssey brought him to lovely San Diego, where he can live out his well-paid days playing next to Tatis Jr. Fun stuff. Castillo greets him with a fastball down and away for yet another ball. (Thom Brennaman kinda acted like this was barely a ball but … uh … are we looking at the same thing here, Thom?)

I love this. Castillo flat-out blasts the $300 million man with a fastball at the tippy-top of the zone. Machado uncorked a mighty hack and came up with air. Note how Castillo’s delivery ends with just a hair of flourish there. He enjoyed this.

With the count even and a runner on, Castillo unleashes the finest pitch of the breakdown and an entrant into the Ode to a Pitcher Hall of Fame (we’re looking into a building right now, probably). Castillo drank Machado’s milkshake with this changeup, fooling him on speed, movement and location, drawing a wild miss of a swing and an amused grin from Machado after.

Check out the slomo on that bad boy:

Machado’s been around. He knows when he’s been had.

Machado is down 1-2 in the count. He got blasted with a hard fastball and spun into a parallel dimension with a darting changeup. What will Castillo follow it up with? He goes fastball away, drawing gentle contact right in front of the plate for a quick groundout. Mejia advances to second.

Hunter Renfroe watches a wild fastball miss into the other batter’s box for ball one. These little episodes encapsulate the Luis Castillo experience. He might depants one of the game’s elite sluggers; he might throw a ball two feet off the plate. Control is a work in progress, obviously.

Again down 1-0, Castillo returns with another nasty changeup that Renfroe swings right over. As Welsh said, he has the stuff to dig out of these holes he digs for himself.

Castillo doubles up on the change, throwing another one and getting the same result. Kind of incredible, isn’t it? That changeup solves a lot of problems.

Renfroe isn’t in a good place here. You don’t want to be down 1-2 to a pitcher with that kind of changeup in his arsenal, especially after proving you can’t touch it. Wisely, Castillo goes back to the well again but misses inside for ball two.

So, 2-2. Mejia on second. Castillo has missed with a fastball, drawn two clean swinging strikes with changeups and missed with the third. Do you go offspeed again? Reach up in the zone with the heat?

Castillo goes changeup and finishes Renfroe with it. Three swings and misses off the same pitch in one at-bat. Incredible.

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Castillo is one to watch. Will he fix the control issues? That might be the last hurdle for him to clear in order to become a Cy Young candidate. The stuff is absurd and he pitches with confidence on both sides of the plate. Reds fans, you’ve got a fun one here.

The hits will start to fall in and he’ll give up some more runs. Don’t despair. If the walks improve, that’ll be enough. He’s close.