The New York Mets are promoting shortstop Amed Rosario from Triple-A, general manager Sandy Alderson said Monday.

Alderson said the timing was decided about six weeks ago, and that the team wanted to get past Monday's trade deadline before bringing up Rosario.

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.

Amed Rosario has 19 stolen bases this season in Triple-A. Jasen Vinlove/USA Today Sports

Alderson said first-base prospect Dominic Smith could be called up soon and "shouldn't be far behind."

Jose Reyes will see time at second base, and Neil Walker will split time between second and first. Asdrubal Cabrera already has been shifted to third.

"The flexibility of our infielders allows us to move some pieces around," Alderson said. "We wanted to get through the deadline and try to resolve some of the position issues that we had."

New York traded first baseman Lucas Duda to Tampa Bay on Thursday for right-hander Drew Smith, and the following day the Mets acquired right-handed reliever AJ Ramos from Miami for a pair of prospects. On Monday, the Mets sent reliever Addison Reed to Boston for three 22-year-old right-handed pitching prospects: Jamie Callahan, Gerson Bautista and Stephen Nogosek.

"Looking at 2018, we felt the bullpen was an area we needed to address," Alderson said.

New York did not come close to trading Cabrera or outfielders Curtis Granderson or Jay Bruce, but Alderson said it was possible deals could come together when players clear waivers during the new waiver period.

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 in the majors behind the Baltimore Orioles (20).

ESPN Stats & Information and The Associated Press contributed to this report.