The Scotland midfielder will be out of action for ten weeks after fracturing his right foot this week.
Brown told Talent Nation.Com: “I’m absolutely gutted that I’m going to be out for so long.
“Fortunately I don’t need surgery which is a big plus. But I’m hugely disappointed that I’m going to miss so many games, especially the Old Firm match next week.
“My aim is to get back to 100 per cent fitness for the New Year game at Ibrox. That’s my No.1 target, so hopefully there won’t be any setbacks.”
He added: “Old Firm matches are always massive but this season they could be even more important in the outcome of the championship.
“Both us and Rangers have maximum points in the league so far – it’s been an unbelievable start to the season.
“The derbies will really go a long way to deciding who is at the top of the table in May.”
