The Hoops were held to a frustrating 3-3 draw against the Dons after a late Lewis Ferguson penalty denied Neil Lennon’s side all three points.
Duffy started the match at the centre of a back four alongside Kristoffer Ajer, with Lennon opting to alter the three-man defence he has employed through much of the early stages of the campaign.
But after an underwhelming display against AC Milan in midweek, Parkhead legend Bonner was once again left questioning the Republic of Ireland international over the weekend, and in particular, his lack of mobility.
Speaking on BBC Sportsound in the aftermath of Sunday’s match, the former goalkeeper said: “The defensive side has let Celtic down today [Sunday], there’s no question about that.
"The worry for me slightly in a defensive situation, they’ve gone back to a back four now, but they were still exposed. Shane Duffy, has a lack of turn of speed, down the side of him especially.
"Throw it up in the air, and I’ve said it many times, there’s no better defender that will come and attack the ball. Sometimes he almost comes and wins things when he shouldn’t be coming, but in general he is very, very good in that department.
"But it’s the balls down the side of him. He’s never been the quickest in the world. People are exploiting it now, they can see it, and again, Aberdeen exploited it at times.”
Duffy joined the Bhoys on loan from Brighton over the summer, and has already established himself as a regular in Lennon’s starting XI, featuring 10 times in all competitions so far this season.
The Parkhead boss has spoken out in defence of the 28-year-old in recent days, arguing that he needs time to shake off some of the rustiness that has lingered from a prolonged period out of the first team picture on the south coast.
He said: “He's only just in the door. He's been thrown in without any real preseason. He'll get better and better – and he'll be a stalwart for the team.
The criticism on the team is justified at times, I get it. But some of it on individual players is unfair. People are looking at every nuance of every player. But you don't get the perfect player or perfect team.
“Shane didn't play any football for nine months. All of a sudden, he's played 14 games in about five weeks.
"He played all of the games for Ireland then he had an abscess in his mouth that was giving him a lot of pain. He flew back into Glasgow last Thursday and had some emergency dental work and we had to roll him out there on Saturday against Rangers.
"He played on Thursday but we're curtailed in that he's got no [Nir] Bitton, Jullien or [Hatem Abd] Elhamed beside him. In the main, his performances have been pretty consistent. I know he's under a bit of scrutiny because people are looking at him for some of the goals we've lost. But we can't pin that on Shane.
"As the season unfurls and goes along, he'll play a huge part. And he's a good type as well.”