This Cleveland Guardians outfield prospect is flying under the radar

Alfonsin Rosario. Make sure you learn that name.

In just a few years time, Rosario will be on pace to make his major league debut. The 21-year-old had an incredible 2025 season in the Cleveland Guardians' minor league system, slashing .251/.345/.461 for an OPS of .806 and knocking 21 home runs. He had stops in High-A and Double-A, but no matter what level he was at, he maintained consistency.

Rosario's flown under the radar in the ranks of Cleveland's many prospects, mainly due to the fact that he was acquired in a deal surrounding reliever Eli Morgan. At the time, Morgan was one of the Guardians' most reliable bullpen arms, coming off his best major league season with a 1.93 ERA and a .256 weighted on-base average against him.

So, when the trade occurred with the Chicago Cubs, much of the focus was on the loss of Morgan and not on who the Guardians got back in return.

Fortunately, that only adds to the excitement surrounding him. With very little recognition of what Rosario brings to the game and his high ceiling, the pressure on him to perform is low. That allows him to develop and improve without having to worry about lofty expectations.

He was selected by the Cubs in the sixth round of the 2023 MLB June Amateur Draft. In his two seasons with them, he wasn't bad by any means. 2024 was his last year with the organization, where he slashed .230/.344/.423 for an OPS of .767. However, he didn't fit with the future plans of the team, especially considering his timeline, at that time, was roughly five years out from a major league debut, and they needed to add help out of the bullpen.

But Cleveland, now more than ever, could use him.

According to the MLB Pipeline, he's described as "a study in extremes as a right-handed hitter. On the positive side, he has more bat speed and strength and generates more raw power and higher exit velocities than most 20-year-olds. But he's also overly aggressive, tries to launch every pitch he sees to his pull side and struggles to recognize or deal with non-fastballs."

The nice thing is that he corrected a lot of those flaws last season, showing growth in composure at the plate, dropping his strikeout percentage from 32% in 2024 to 27% in 2025. That occurred even as he took a step up in minor league levels.

On the fielding end, he's primarily played in center due to his speed, a spot that Cleveland's been wrestling with to fill the last couple of years.

The Guardians do currently have a lot of young, talented outfielders who are slated to make appearances in the big leagues in 2026, most notably Chase DeLauter and George Valera. That makes Rosario's window to improve and work his way up the system longer, which may be a good thing.

Rosario will more than likely get his first chance at Progressive Field in the 2028 or 2029 season.