Ahead of Sunday's SPL clash with St Mirren in Paisley, the Hoops boss gave an injury update at the club's Lennoxtown training complex.
He said: "Scott Brown had surgery in the break and so he is looking at a month, four to six weeks.
"Thomas Rogne has a hamstring strain and he will out for two to three weeks.
"James Forrest (back) is continuing his rehab at the minute.
"Joe Ledley didn't train today (Friday), due to a slight groin strain but will hopefully train tomorrow and Adam Matthews (hamstring) will train on Monday.
"Charlie Mulgrew is fine, he had a tight hamstring before the Serbia game and Gordon Strachan didn't take any chances with him obviously, but he came through training okay."
- Sports & Recreation
- Thomas Rogne