This story was excerpted from Christina De Nicola’s Marlins Beat newsletter. To read the full newsletter, click here. And subscribe to get it regularly in your inbox.

What were you doing at 18 years old?

This summer, the precocious Keyner Benitez (Miami’s No. 21 prospect) advanced to Single-A Jupiter and more than held his own as the youngest pitcher in the Florida State League.

When the Marlins inked Benitez to a $225,000 bonus as part of their 2023 international signing class, they knew of his advanced pitchability. But the left-handed teenager has progressed quicker than expected, a little more than a year removed from his professional debut in the Dominican Summer League.

“We saw components of what made [the international department] so excited, a big reason why we brought him here to the States,” director of Minor League operations Hector Crespo said. “As soon as he got here, just from a physical standpoint, a mentality standpoint, he kind of hit the ground running. So really excited about where he's at.”

It took just three outings (two starts) at the Rookie-level Florida Complex League for Benitez to receive a promotion to Jupiter four days after his 18th birthday. In 13 games (11 starts) for the Hammerheads, he compiled a 3.12 ERA and a 1.20 WHIP with one save while facing competition averaging nearly four years older.

What encouraged the Marlins most was Benitez’s mentality. Despite his age, Benitez felt like he belonged.

“The biggest jump right now in Minor League Baseball, in my opinion, is that jump from the Complex League to full-season Jupiter,” Crespo said.

“I'd say, [it's] very rare for a guy to have the composure that he does, to not scare. I think it's easy once you get in more of that stadium environment to scare a little bit. But as soon as he got to Jupiter, he picked up where he left off in the FCL and competed. He took his licks at times, but for the most part, he was able to compete. And [he] kind of cemented why we were so encouraged and pushed him over to Jupiter, because we felt he was ready.”

According to MLB Pipeline’s scouting report, Benitez’s quick arm and quality extension means his pitches get on hitters quickly. Though his strike-throwing fluctuates at times (as evidenced by his career 4.2 BB/9 rate), he is able to repeat his delivery better than most teenagers.

Benitez’s three-pitch mix includes a two-seamer, which he is more comfortable throwing than his four-seamer at the moment, a curveball and a developing changeup.

“It's 92-95 [mph] with feel to pitch,” Crespo said. “I think the biggest thing that separated him than most of our younger guys is his ability to pitch in. He's fearless, and he just commands all quadrants, but really with an emphasis on pitching inside to right-handers.”

Here are a handful of other lesser-known prospects that Crespo highlighted:

LHPs Jack Sellinger and Justin Storm
Selected in the 14th round of the 2023 MLB Draft, the 24-year-old Sellinger posted a 2.70 ERA and a 1.11 WHIP with only one homer allowed in 32 outings between High-A Beloit and Single-A Jupiter. Miami chose Storm, who turned 23 on Thursday, in the seventh round in 2023. He had a 1.81 ERA and a 1.13 WHIP in 31 combined appearances at Beloit and Jupiter, with only one homer surrendered as well.

“I always have the extended spring [camp] talk and try to encourage the guys wanting to break out to a full-season team and end up staying back,” Crespo said. “Those are the two main examples of guys who started the year in extended but didn't let that waver. And they continued to get better and develop and compete, and then they ended up finishing in Beloit. It's easy to be defeated once you start the year in extended, but it's cool to see what those guys were able to do by just continuing to get better.”

RHP Jake Brooks
Brooks, 23, had a 2.18 ERA and a 0.99 WHIP in 23 games (21 starts) between the High-A and Single-A levels. He was taken in the 11th round of the 2023 MLB Draft.

C Ryan Ignoffo
The 24-year-old hit .324/.376/.469 in 103 games between Beloit and Jupiter while learning a new position.