Brown spent 14 years at Celtic and won 23 major honours at Parkhead before he left the club at the end of last season.
He joined Aberdeen both in the capacity of a player and first-team coach and has made 14 appearances for the club in all competitions this season.
The veteran midfielder is almost certain to be in the starting eleven when Celtic visit Pittodrie on Sunday, but Ferguson is confident that facing his former club will not be an issue for Brown.
He is sure that the midfielder will go down as a Celtic legend due to his achievement at Parkhead, but he will give it his all to help Aberdeen win the three points when the two sides square off on Sunday.
Ferguson said on the Go Radio Football Show: “I don’t think it will make a difference. I think that’s in the past.
“He had a brilliant time there, successful time, was a great captain, won many trophies, but Aberdeen pay his wages now and that’s where his allegiances have got to lie.
“He will be going out trying to get three points because Aberdeen, for the squad they have got and the backing that Stephen Glass has had, they should be further up the league for me.”
Aberdeen have lost three league games in a row and Brown will hope to get them back on track against his former side this weekend.