Asked if he would consider yet another comeback if the Scots reach their first major finals since France '98, the Celtic captain said: 'Football's a funny game and you never know.
'They still have two games to get through but... you never say never.
I'm in a good place fitness-wise and in terms of my body. I make sure I keep myself ticking over.
'The international breaks have been incredible for me - they've allowed me to go away and relax, play golf and recharge my batteries.
'That's been good for me and I retired from international football to prolong my career and I don't want to be that guy who keeps quitting and then thinking he can come back.
'I'm going to be 35 soon and we're very strong in the middle of the park - there's a lot of young lads in that area.
'It's been hard for me to watch the games because you always want to be playing in them but, at the end of the day, I need to look after No1.
As much as I don't see a problem with what he said about the SPFL postponing matches, he should not be recalled if we get to the finals.