The 19-year-old started in the Europa League qualifier against AZ Alkmaar and came on as a substitute in Celtic’s defeat to Rangers in the derby at Ibrox last month.
He played 45 minutes against Ross County at the weekend as well and Ferguson believes that it is clear that Celtic manager Postecoglou rates the 19-year-old highly as he did not sign another left-back in the summer.
The former Scotland midfielder stressed that the Celtic manager feels that Montgomery has the talent to make it Parkhead.
Ferguson also insisted that the player is clearly talented, with the potential to be a top player and believes now he just needs a run of games in the starting eleven to take the next step.
The former Scotland international said on the Go Radio Football Show: “I have only seen highlights and obviously watched the Old Firm game live here when he came on.
“He certainly looks like potential and it tells me why Postecoglou didn’t go and sign another left-back because that was an area where you would probably say they needed strengthening.
“I think it was an emergency [to use] the young man but he clearly thinks that he has got enough in the locker to be a Celtic player.
“From what I have seen, he is going to be a real player.
“What he needs is an opportunity to start and then play 5, 10, 15 or 20 games and we really see what he is made of.
“But certainly, he has potential.”
Montgomery has made just ten appearances for Celtic and is a Scotland Under-21 international.