Brown has agreed to a pre-contract to join Aberdeen in the summer and has two more games left in the tank for Celtic.
He will leave Celtic with more than 600 appearances to his name, 22 major trophies and after captaining the side to a quadruple treble at Parkhead.
Former Celtic star Charlie Nicholas recently said that Brown will be easy to replace for the Bhoys and Craigan admits that on the pitch that could be the case as Brown’s performances levels have dropped off from his previously high standards.
However, he stressed that the 35-year-old’s impact beyond the pitch and how he led the club by example behind the scenes is something Celtic are going to find a lot harder to replace.
Craigan said on the Go Radio Football Show: “Do you know what he is 35, I think he may be easy to replace on the pitch because of his age, his performances have dropped a little bit, his legs are not what they used to be and his energy is not what it used to be.
“So yes, I think he can be replaced on the pitch based on current form.
“But when you look at his overall stature and how he has led the club, I imagine behind the scenes would be the one that will be harder to replace.
“Driving the tempo in training, demanding of the new players coming in, setting standards, training properly, doing everything right – that’s what a proper captain does behind the scenes, lead off the pitch and just not on it.
“I think that will be the harder one to replace.”
Brown will be joining Aberdeen as a player and will also be part of manager Stephen Glass’ coaching staff.