Rosario is the top-ranked prospect in Major League Baseball, according to ESPN’s Keith Law. Rosario will make his big league debut Tuesday against the Colorado Rockies and will be in the starting lineup.
Alderson said first-base prospect Dominic Smith could be called up soon.
Rosario, 21, is hitting .328 with seven home runs and 58 RBIs this season at Triple-A Las Vegas. He also has 19 stolen bases. The Mets have 25 stolen bases as a team, the second-fewest total in the majors behind the Baltimore Orioles (20).
ESPN Stats & Information and The Associated Press contributed to this report.