Sodo Mojo’s Top 10 Mariners Prospects: #8 Ronald Rosario

A farm system as bad as the Seattle Mariners needs guys to “pop”. The prospect that rockets up their board by surprising scouts with his tools and overall game. For the Mariners, that player may very well be Ronald Rosario.

Ronald Rosario, a 20-year-old international free agent signed by the Mariners in 2013, finally made his state side debut in 2017. The Dominican born outfielder spent his first 3 season playing in the Dominican Summer League, where he showed steady growth every season.

Rosario made the jump to Everett after a short stint in the AZL, and showed real promise in 40 games with the Aqua Sox. During his stint with the Mariners Low-A affiliate, Rosario hit .294/.355/.516, with 6 homers, 6 doubles, and 2 triples in 182 at bats.

The high slugging percentage is encouraging, as power is the biggest question in Rosario’s game. Scouts have said that the slender Rosario is starting to fill out his 6’2″ frame, which could bode well for an uptick in power.

Scouts also report that Rosario has “above-average bat speed” that should lead to an average hit tool. If the power develops along with the approach, Rosario could be a big league outfielder.

In the outfield, Rosario is a work in progress. He does not posses top end speed, and needs to improve on his routes as a result, but has handled all 3 outfield positions in his career. Most seem to believe Rosario is best suited for a corner spot, but there is still defensive upside to his game. Rosario has a good enough arm to handle right field, but might be best suited for left.

Scouting Grades(20-80)- Bat: 50 Power:50 Run:50 Arm: 55 Field:50 Overall: 50

While Rosario is a big question mark, in a weak farm system like Seattle’s, he is exactly the type of players the Mariners can dream on. He’ll likely start the season in Everett or Clinton, but should see some time in Modesto. A trip to AA Arkansas is not out of the question, but the Mariners have no reason to rush a player like Rosario.

Next: Top 10 Mariners Prospects: #9 Joe Rizzo

Rosario has never played more than 53 games in a season, so making a jump to full season ball is crucial to his development. If he can replicate his numbers over 100+ games in 2018, Seattle might have a legit prospect in Rosario. If not, they might have a 4th or 5th outfielder in 3 years.