How the Diamondbacks Uncovered This Hidden Bullpen Gem

The Arizona Diamondbacks might have a hidden gem in their bullpen: flamethrowing right-hander Juan Morillo. The 26-year-old rookie found his way into his first career major league contest on Saturday, and shut the door on a D-backs win on Tuesday.

It took a meltdown by relievers Bryce Jarvis and Joe Mantiply, coupled with an injury to A.J. Puk to force Arizona's hand, but Morillo was one of three relievers who got the call on April 19, and he looked ready for the lights in his first taste of MLB.

Morillo walked the first batter he faced, but tossed a scoreless inning, punctuating it with a pair of strikeouts against Kyle Tucker and Michael Busch.

"For me, it was everything," Morillo told Diamondbacks On SI's Jack Sommers. "I signed for the first time in 2015. So, now I'm here. I thank God for giving me this opportunity, and the organization too. It was a special moment for me, the debut..."

Morillo's fastball sat in the 98 MPH range, and even reached into triple digits. He relies primarily on that excellent fastball, but also throws a sharply-breaking slider and an occasional changeup.

On Tuesday, Morillo was given the nod again. This time, the task was to close out a 5-1 win over the Tampa Bay Rays. Morillo did so in similar fashion, walking the leadoff hitter, before inducing a groundball double play and ending the inning scoreless and hitless with an emphatic strikeout.

So who exactly is this under-the-radar weapon, and just how did he end up on the Diamondbacks' roster?

Morillo began his career at a young age, signing a minor league deal with the Los Angeles Dodgers at just 16 years old back in 2015. After a long, slow climb through the minors, he spent two lengthy stints on the 60-day Injured List, effectively ruining his respective 2021 and 2022.

But once healthy, Morillo faced another challenge — one that is extremely common for pitchers of his archetype. The right-hander simply couldn't command his arsenal. In 2023, he issued a rough 6.21 walks per nine innings across Low- and High-A ball, an unsustainably high number.

The flipside, of course, was his nearly 13 strikeouts per nine. But the Dodgers ultimately decided Morillo's electricity wasn't worth his command issues, and he became a free agent in 2024.

But something began to click for the fireballer. It began with a stint in the Venezuelan winter league. Over 16 winter appearances, Morillo's BB/9 (3.9) was nearly half of what it was in the Dodgers' farm.

Morillo cited his experience in the winter league as a driving factor to his eventual MLB debut.

"I think I learned [a lot] in winter ball last year. I think it helped me a lot to get in there, to throw the ball over the plate all the time, because that's all we have to do. That's what we practice every day. That's what we do every day. I think now I'm here because I did it. I got a little bit of control on that," Morillo said.

But it wasn't just his stuff that put him on Arizona's radar. Morillo said Diamondbacks' backup catcher Jose Herrera was instrumental in getting him in front of the right people. Herrera and Morillo were teammates in the winter league, both playing for Aguilas del Zulia.

"I talk with Jose Herrera a lot, and he talked to me a little bit about the organization, what they're looking for, and that's why I'm here too. ... I was a free agent last year, and then I was talking with my agent, and she told me that the D-backs [had a] number for me, and I took the D-backs," Morillo said.

For Herrera, it was an instant evaluation.

"As soon as I saw [Morillo] down in winter ball, I knew there was something special in that arm," Herrera told Diamondbacks On SI. "I talked to him when I got there and got to know him. He's a good kid. He works hard and he deserves to be here. I went into his mind and pushed him a little bit to sign with Diamondbacks.

"I don't want to say that I was a big influence, but I was talking to him," Herrera said.

The catcher said he tried to sell Morillo on the Diamondbacks' organization, and even went so far as to bring Morillo up to his own agent — who in turn contacted Arizona's front office.

"I was telling him our approach in the game and how special it would be if he was part of the organization. I mean, I've been in the Diamondbacks' my entire life, and I know how special [that] arm was to the org. I'm glad that he signed with us, and look where he's at right now," Herrera said.

Herrera noted Morillo's exceptional power fastball. But it was more than just the stuff that stood out about the right-hander.

"[He was] able to control the running game when I saw him in winter ball, that was something special because nobody does that. Nobody paid that much attention in winter ball and he was capable to do those little things that are important to me as a catcher," Herrera said.

"I'm looking forward to see him just getting the best of his opportunities and keep continuing to grow."

A scoreless single inning is hardly anything to bank on in entirety. But it does seem as if the flamethrowing Morillo has begun to tangibly improve his command. Over seven Spring Training innings, Morillo walked just one batter against 10 strikeouts — all without allowing a run.

And in a small sample size of Triple-A Reno, it's looked similar. Morillo has just one earned run over 6.1 innings. He's walked two and punched out eight.

Even if the command issues surface once more, it certainly appears that Morillo is on the right track. After just two innings of major league work, it seems as if the D-backs might have found something in the 26-year-old righty.

"I just trust the process, I just believe in me and [work] every day," Morillo said. "No matter what it was before, when I got surgery, my mind was just looking forward, keep doing what I'm doing, and we're here."

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