Mam will be left to make his rugby league comeback in Queensland Cup this weekend, after being overlooked for the Broncos' clash with South Sydney on Friday.
The Brisbane star has not played since being injured last August, before copping a nine-match ban for crashing a car while driving unlicensed and with drugs in his system last October.
Maguire insisted the call to leave Mam out of the Rabbitohs clash was purely a football-based one, with the 22-year-old told to prove his form for Souths-Logan.
"Firstly, he's got to play," Maguire said.
"I always look at teams and building culture in teams that you have to earn the right to put the badge on. It's something the players have all spoken about.
"What I mean by that is actually performance on the field as well, and off the field.
"Ezra has to go away and perform now and show the way he can play and then I'll look at it from there."
Maguire said he was confident Mam would be able to handle the spotlight, with the focus likely to remain on the Indigenous star until an NRL return comes.
Mam was fined $120,000 by the NRL and has since attended a rehabilitation facility in the time since the incident, with the Broncos coach believing his half had learnt from the affair.
And Maguire was adamant this was not a case of the 2023 grand-final star having to win back the respect of his teammates.
"I don't know if you call it respect," Maguire said.
"It's about performance. You have to perform to be able to show yourself.
"Every player who has played until this point have all earned the opportunities in the way they have trained and way they have performed. I am big on that."
Maguire said he did not know when Mam's likely return would come, with part of that decision also the form of Ben Hunt and Adam Reynolds as a halves pairing.
The fifth-placed Broncos have been one of several sides to be wildly inconsistent this year.
Hunt will likely move to hooker on Mam's return and Brisbane may also lose Hunt to State of Origin duties, but that will not come until later in the year with byes before the first two games.
"Ezra getting back to the form that we know he's capable of, he's got to put a lot of pressure on pushing himself into the team," Maguire said.
"Let's see how he plays. For him he has done a lot of work in the background.
"For any player who hasn't played for five months, you can't just think you're going to come out (and fire).
"You've got to be on. Every play matters.
"When you haven't been out there practising all the little movements ... teams are going to try and put pressure on you. You've got to handle that pressure."
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