Brown has agreed a pre-contract to join Aberdeen at the end of the season and he will be moving to Pittodrie in the capacity of a player as well as a coach.
The midfielder joined Celtic in 2007, has won 23 major trophies over 14 years and has made more than 600 appearances for the Bhoys.
Celtic fans are lamenting the fact that the club didn’t do enough to keep Brown and even Petrov revealed his frustration at the scenario.
He feels Celtic are in need of leaders such as Brown in their squad and it is flabbergasting that the club are allowing that experience to move to Aberdeen who would benefit from them.
Petrov said on the Celtic Huddle Podcast: “We are about to lose one of the biggest and the most charismatic leaders in Celtic’s history in Scott Brown.
“We are talking about a person who has won 22 titles [23 trophies], who has become an idol for many fans.
“And we are about to give him to someone else to show what he knows and how he leads and we are not keeping him.
“This is really frustrating to see but we have to wait and see if that’s going to be true or they can do something about it.”
Aberdeen manager Stephen Glass was Scott Brown’s team-mate at Hibernian and has a strong relationship with the veteran midfielder.