Montero was optioned to Triple-A Albuquerque on Thursday, Nick Groke of The Athletic reports.
Montero will head back to Triple-A after he spent a little over three weeks with the big-league club. While in the majors, the 23-year-old went 4-for-21 with two doubles and three runs scored over seven games. Kris Bryant was activated from the paternity list Thursday and will take Montero's spot on the active roster.