Montero (elbow) has posted a 10.50 ERA with 10 strikeouts over six innings at Double-A Frisco this season.
Montero was forced to miss the entire 2018 campaign after undergoing Tommy John surgery, though he was able to return to game action with the Rangers' Arizona League affiliate in mid-June and has since been coming out of the bullpen at Double-A. The right-hander doesn't appear to have found his groove just yet, but he'll likely need a considerate amount of time to get back up to speed after rehabbing for a year.