“We watch this team every day and we’re constantly looking for ways to get better,” said John Ricco, the Mets’ assistant general manager. “But at the same time, you have to be sure that the guy you bring in is going to make you better. He might make you better for a short period of time, but if he’s really not ready, you’re not only doing him a disservice, but you may be doing the club one.”

The Mets’ top decision-makers — General Manager Sandy Alderson, the special assistant J. P. Ricciardi and Ricco — receive daily evaluations of the team’s minor leaguers. And Alderson, who visits the Mets’ minor league affiliates during the season, watched Rosario play this week in Salt Lake City.

“We don’t sit there every day saying, ‘Should we bring him up today?’” Ricco said of Rosario. “But it’s a constant conversation while watching what’s going on here and trying to figure out what’s the best situation and the right time.”

And although the Mets have been pleased with Rosario’s progress, they believe he could use more seasoning. He has not played a full season above Class A. He hit .341 at Class AA Binghamton in 2016, but in just 54 games.

“There are certain things you can only get with repetition,” Ricco said.

Jose Reyes was 19 and David Wright was 21 when they made their Mets debuts, and both had played fewer games above Class A than Rosario has. Michael Conforto was called up from Binghamton at age 22 in 2015, when the Mets were desperate for offense. It was just a year after he was drafted in the first round out of Oregon State.

Conforto helped the Mets reach the World Series that year, but he struggled so much in 2016 that he was twice demoted to the minor leagues. This season, he has been the Mets’ best hitter.