Rosario mingled with top prospects like 2012 first-round pick Gavin Cecchini and 2011 first-rounder Brandon Nimmo. Rosario, like even the most highly touted players from the Dominican Republic, will go through a more measured developmental process.
When the team officially signed him on July 2, vice president of scouting and player development Paul DePodesta praised Rosario for his athleticism and intellect. Both qualities have been on display in Florida.
"He's got a lot of tools," minor league field coordinator Dick Scott said. "He's an interesting guy. And he's got a lot of aptitude for a young kid. He's just devouring information down here, putting it into play very quickly. So that's really encouraging."
Rosario bats and throws righthanded. He stands 6-foot-2 and weighs about 170 pounds. The team hopes he can develop power as he adds pounds to his frame.
Team officials expect Rosario to spend the 2013 season in the Rookie-level Dominican Summer League. Right now, getting playing time is what matters most.
"I believe we'd really be doing him a disservice by trying to rush him to (a domestic) team," Scott said. "He needs to play, get at-bats, get reps down there."
Rosario speaks limited English. He expressed nervousness about taking batting practice at Citi Field on Aug. 21. "I was kind of scared and kind of nervous," he said through an interpreter. "But it's getting better."
• Wally Backman will remain with the Mets as manager of their new Triple-A Las Vegas affiliate. He managed Triple-A Buffalo last season. Backman was one of four finalists for the big league job given to Terry Collins in the winter of 2010. Collins is working without a contract beyond 2013 and Backman is considered a candidate to potentially replace him.
• Second baseman Danny Muno was delayed in joining his Arizona Fall League teammates in October. The team cited "personal reasons" for his late arrival. The 23-year-old missed 50 games during the regular season after violating baseball's performance-enhancing drug policy. Muno hit .280/.387/.412 with high Class A St. Lucie this season.