Montero, who tweaked his groin in Monday's game against the Dodgers, was kept out of the lineup Tuesday and Wednesday.
"He's not ready to play yet," Arizona manager Kirk Gibson said Friday. "He's not ready to go catch a game right now at this point. He's got more range of motion, it feels much better. We put him through a lot of baseball activities and movements today, so we'll see how he reacts. He's not a fast guy, but he runs very hard."
Is it realistic to think he could play at some point this weekend against the Brewers?
"Yes, it's possible," Gibson said. "Tomorrow's possible, but I'm not sure yet. We'll see."
The D-backs added backup catcher Konrad Schmidt from Triple-A Reno earlier this week, and they will have him until Sunday when they will need to clear a roster spot for right-hander Daniel Hudson, who is set to come off the disabled list.
"If you throw me out there right now I'll play," Montero said. "If they ask me how I feel, I say great, but I understand the point [that] there's no reason to force it today when we can easily give it another day or two."