Mejia was assigned to the Florida Complex League from Single-A Palm Beach earlier this month.
He has eight walks, three strikeouts, two steals and zero hits through four games in the complex league. Mejia was originally assigned to Single-A on May 23, then was placed on the temporarily inactive list for four days in early June and played in one more game at Single-A before getting assigned to rookie ball June 12. He is one of the Cardinals' top prospects in the lower levels.