Rosario quickly climbing Texas' prospect leaderboard

This story was excerpted from Kennedi Landry’s Rangers Beat newsletter. To read the full newsletter, click here. And subscribe to get it regularly in your inbox.

OAKLAND -- Alejandro Rosario was planning to go back to the University of Miami for his senior season. After all, he had just posted a 7.11 ERA in 74 2/3 innings in his junior season in 2023, and he wanted another year to try to improve his Draft stock.

But the Rangers saw something intriguing in him, something their player development system could work with. Texas selected him in the fifth round of the 2023 MLB Draft, set on having that potential materialize into something more on the field.

Rosario recalls that the club told him what his strengths were, and how to best maximize them for success. The Rangers liked the way he attacked the strike zone, first and foremost. But they wanted him to use his pitches in a different way and alter how he attacked hitters specifically.

“He had an ability to place the ball where he needed to place it,” said assignment general manager for player development Ross Fenstermaker. “We thought that there was an underutilization of certain pitches, particularly fastballs in parts of the zone, and maybe the split finger fastball that he throws as well.

“When we looked at it, we thought we could tweak a few things and alter the pitch mix, so to speak, to get the most out of his natural ability. To his credit, he gave it a try spot and in having experienced success, I think it just builds upon himself and doubles down.”

It worked, too. Rosario skyrocketed from unranked in MLB Pipeline’s Top 30 prospects in the Rangers' system to No. 3 midway through the Minor League season. He opened 2024 with Single-A Down East, and he thrived with a 2.11 ERA across 10 starts before receiving a promotion to High-A Hickory on June 25.

By year’s end, he was named Texas’ Minor League Pitcher of the Year, after posting a 2.24 ERA with 129 strikeouts and just 13 walks in 18 games (17 starts) between Single-A Down East and High-A Hickory. His 9.92 strikeout-to-walk ratio this season is the highest single-season mark by a Rangers farmhand since it was first tracked in 2005 (min. 80 IP).

He earned yet another promotion to Double-A Frisco on Sept. 3, but never made an appearance after being placed on the Developmental List on Sept. 10.

“It’s definitely unexpected, especially with the three years I had at the University of Miami,” Rosario said. “Last year, I got into instructs after the Draft and got to work in the pitching lab with the pitching coordinators and the staff. They helped me. I went along with their plan, and I trusted it, and it turned out to be a good year.”

Despite Rosario being shocked by his own success, the Rangers weren’t. After all, Fenstermaker explained, he was a top talent coming out of high school, and he could’ve been selected in the top three rounds back then. But Rosario wouldn’t waver from his commitment to the University of Miami. He was a member of Team USA as an amateur and competed in multiple major tournaments.

This isn’t a player who is unaccustomed to success. Even though Rosario logged a 6.53 ERA in three seasons with the Hurricanes, the Rangers saw enough potential in him.

He worked to make sure that potential came through on the field.

“I think there's a lot of growth that's happened there, more than anything, he’s experiencing success at a level that he probably hasn't quite experienced yet,” Fenstermaker said. “I think he's still coming into his own as a pitcher and figuring out who he is and what he does well. I think he did an exceptional job of that this year.”