Celtic chief executive Peter Lawwell is confident they can improve Gordon Strachan's squad in the summer to meet his ambitions of reaching the Champions League quarterfinals next season.
"We try to keep an edge elsewhere and that's what we have to do as a Scottish club. We operate at our level of the transfer market and that is Scottish club level. We signed Scott Brown for £4m and will continue to do that. However, we are investing heavily in scouting and we are the best in sports science, trying to make our players better. I think you have seen that with Aiden.
"We are not a selling club, either. Aiden has three years left and we are relaxed about the situation. There has been no contact from anyone about Aiden or anyone else."