Eighteen until August, Rosario is currently the youngest player in the High-A California League, spending a bulk of his innings for Lake Elsinore manning second base. Short and muscular with average athleticism and defensive value, Rosario brings a quality hit/power combo with the ceiling of an everyday second baseman.
Rosario’s up-the-middle and opposite field approach yield hard line-drive contact. He works counts and has a feel for the zone, taking competitive at-bats against much older competition. He shows good feel for the barrel, and when you add it all up, there’s a chance for a future 50-grade bat at the big league level. His average raw power is impressive for a player his age, and he shows signs of already understanding how to work his way to a fastball count to take a bigger swing and do damage. Ultimately, his size and approach are more that of a doubles hitter with occasional over-fence power, though he certainly isn’t light with the bat by any means. Defensively, he has an average arm, and good footwork and first-step quickness allow him to play at either second or third. The offensive profile is more that of a second baseman, and while he brings infield versatility, Rosario is likely to slot in full-time at the keystone as he gets closer to the big leagues.
With a well-rounded set of tools that all grade at 45 or 50, the ceiling is an everyday second baseman on a second division club. On a contender, this type of player occasionally is relegated to more of a utility role, though Rosario projects as a quality bench piece if that is indeed his future at the highest level. His plus baseball instincts and fiery style of play tie everything together and allow him to get the most out of his tools.