The Cincinnati Reds are young and rebuilding, so it’s not too much of a surprise that, this year, they’ve had more players make their major-league debuts than any other team. Yesterday, a pitcher named Ariel Hernandez showed up for the first time. He was tasked with some early innings in relief of an unsuccessful starter. Although it’s never easy to make one’s first-ever big-league pitches, some of the pressure is off when your team’s already losing 10-4.

Hernandez entered in the bottom of the fourth. In this post, I’d like to try something. He entered with one out. It took him six pitches to get out of the inning. Hernandez completed two more innings afterward, but I want to look at those six pitches alone. And here’s the idea: I want to estimate Hernandez’s projected ERA at each instant. That is, I want to take a stab at his rest-of-season ERA given only the information provided to me. I knew nothing about Hernandez before, and the same presumably goes for many of you. He’s working now to fill up a blank slate.

Here goes nothing! Six Ariel Hernandez pitches. His first six meaningful pitches, against major-league hitters.

Hernandez, again, showed up in the fourth. He was new to me, and as he warmed up from the mound, viewers were given this visual.

There’s not a lot you can do with eight innings. Low opponent average, but, eight innings. High strikeout total, but, eight innings. Moderately high walk total, but, eight innings. It’s an extremely small sample, so we can’t lean on it too hard. What’s already evident: Hernandez is a right-handed reliever. He was coming up from Double-A, not Triple-A, which is slightly unusual. Because I hadn’t heard of Hernandez before, I wasn’t aware of any hype. Best I could guess is that Hernandez would be something like a league-average reliever. Seems like the safest assumption. The average reliever at present has a 3.89 ERA.

Projected ERA after 0 pitches: 3.89

The first pitch of the appearance was moments away. Look, here it is!

As I think about it, I’m surprised — I’m surprised that there was a swing at Hernandez’s first-ever pitch. You’d think the hitter would want a look, and you’d think Hernandez might be a little too amped up. On the other hand, perhaps the thinking was that Hernandez would try to just lay one in there to gain some instant comfort. So, a swing, a grounder, and a near-double play. An immediate takeaway is that the Hernandez pitch, a fastball, was clocked at 98 miles per hour. That’s good! It was also located well down and away, which is kind of remarkable for a pitcher throwing for the first time. Good arm strength, good location. That the pitch was put in play suggests it might not be a swing-and-miss fastball. Maybe more of a power sinker? There’s more information coming, but Hernandez’s first pitch was more good than bad.

Projected ERA after 1 pitch: 3.70

Keon Broxton got the chance to try to hit Hernandez with two down. First-pitch fastball, again at 98. So, the velocity doesn’t appear to be a fluke, not that such a thing can even really occur. We know Hernandez throws hard. He looks to have a relatively short stride, with a low arm slot, and that reduces his perceived velocity, but increases his amount of “funk.” This fastball isn’t located quite as well as the first one. It’s up, compared to the target, and it drifts over the plate. The location still isn’t horrible. Broxton kept himself from offering.

Projected ERA after 2 pitches: 3.65

Another 98. Already, we can take the velocity for granted. The location here is similar to the previous pitch, up and over the plate, compared to the target. That’s not great, and neither is the runner advancing to second. But, most relievers are bad about controlling the running game, especially when they’re making their debuts. Hernandez wasn’t going to be too concerned about a runner on first with two outs in a six-run contest. Also, hey, a swing and miss. Sure, this is a Keon Broxton swing and miss, not a Daniel Murphy swing and miss, but you like to see whiffs at elevated fastballs.

Projected ERA after 3 pitches: 3.55

Oh.

For the first time, we see Hernandez throw a non-fastball. It moves like a curveball, but it flies with slider velocity. This pitch is clocked at 88, and, even more, it’s located perfectly, given the count. That’s a textbook 0-and-2 breaking ball, except that no textbook would suggest an average pitcher just go out and unleash a high-80s curve as if that isn’t an absurdity. The one drawback is that Broxton doesn’t flail. Somehow, he takes this pitch. For Hernandez, it’s a ball, but it’s a quality ball.

Projected ERA after 4 pitches: 3.25

Back to the heater. 99. Hernandez gave Broxton a little something extra. This time, the target is inside, not away, and Hernandez more or less executes, missing slightly up and in. Broxton backs off, but now he’s seen Hernandez on both sides of the plate. I’m not seeing any big issues with mechanical repeatability. It’s just five pitches, but it’s five pitches fueled by adrenaline. Fairly encouraging.

Projected ERA after 5 pitches: 3.20

Perfection. Perfection with the breaking ball, again. Hernandez spins one in at 87 miles per hour, and Broxton’s helpless. The reality is that Broxton strikes out plenty, and he strikes out looking plenty, but the reality is also that Hernandez didn’t give him a chance. When you have a pitch that moves like that, and when you can command it like that — as a reliever, then there’s not much stopping you. The first time Hernandez spun a curve, Broxton watched it, and maybe that was because Broxton hadn’t seen it yet. By this pitch, he’d seen it. Still couldn’t pull the trigger. Hernandez strides off, triumphant.

Projected ERA after 6 pitches: 2.90

As I look at things, maybe I’m being too aggressive with my guesses. Craig Kimbrel is projected for a 2.83 ERA. Cody Allen, 2.93. Edwin Diaz, 2.94. A pitcher needs to earn that sort of company. It’s just that I found Hernandez to be that impressive, and he went on to throw perfect fifth and sixth innings, picking up another four strikeouts. Hernandez’s 2017 sample remains small, yet his debut could not have been better, and the stuff is obvious. Really, the stuff has been there a while. I haven’t even mentioned Hernandez’s back story.

Here it is, in graphical form:

When he was younger, Hernandez couldn’t get out of his own way. His fastball could reach the triple digits, but he had all the control of a cheetah in an ice rink, so the Giants eventually grew frustrated and released him, without his ever having climbed above Rookie ball. A shoulder problem prevented Hernandez from pitching in 2014, and it cost him some velocity. He did get it back, and after a brief stint in indy ball in 2015, Hernandez signed with the Diamondbacks. Yet his control was still bad, so he wound up unprotected, and selected by the Reds in the Rule 5 draft. I should say, the minor-league part of the Rule 5 draft.

And then Hernandez took a step forward. You can see it in the plot, with Hernandez dramatically improving his location. J.J. Cooper wrote about Hernandez last October, and Hernandez’s improvement was credited to adjusted mechanics and a different, more curveball-heavy approach. Hernandez didn’t and doesn’t have pinpoint precision, but with his stuff, that would be unnecessary. And the early results suggest further improvement in 2017. Already, last season, Hernandez allowed a .136 batting average, with opponents slugging .164. Hernandez has now pitched for the first time in both Double-A and the majors, and his numbers are terrific. He’s armed with two plus pitches. That’s all a reliever could ever need.

A few months ago, when Eric examined the Reds’ system, he ranked Ariel Hernandez at No. 18. An excerpt:

Hernandez has 30 control and won’t pitch for very long in the big leagues without significantly improving his ability to throw strikes. Even during a dominant final few weeks of the season, Hernandez walked 10 over 15 innings. He’s 24 and hasn’t pitched above A-ball, but if Hernandez learns to harness his stuff he’s going to pitch at the back of a big-league bullpen.

Last year, Hernandez threw 60% strikes, allowing a .437 OPS. So far this year, against advanced competition, Hernandez has thrown 63% strikes, allowing a .311 OPS. In the debut, I didn’t see any problems with Hernandez repeating his mechanics, and there’s no faking a three-digit fastball. Even better, there’s the breaking ball. I looked at all of the 2017 curveballs and sliders. Two other big-league curves are easily the closest comps to what Hernandez just threw on Monday.

A Breaking Ball Comparison Pitcher Hand Velocity H Mov V Mov Ariel Hernandez R 87.6 5.1 -5.4 Craig Kimbrel R 86.6 5.3 -6.3 Lance McCullers R 86.3 4.6 -5.7 SOURCE: Brooks Baseball

Ariel Hernandez, and two of the world’s best curveballs. Hernandez is right there with Kimbrel and McCullers in curveball speed, horizontal break, and vertical break. Hernandez also throws 98, and he has better control than ever before. I don’t know how much more there is to need to see. I suppose we need to know how much Hernandez has truly improved his location. But if he has even half of a clue, good heavens.