The Mets are about to promote one of the most promising pitching prospects they've developed in years. No. 3 Mets prospect Nolan McLean, ranked 37th in baseball, will make his Major League debut Saturday in a start at Citi Field against the Mariners,

The Mets selected McLean over Brandon Sproat, who has pitched at a high level recently for Syracuse after struggling to begin the season. Manager Carlos Mendoza indicated this week that whichever pitcher the Mets promoted would receive an extended look in the rotation, rather than a one-shot callup.