The reason commons fitness doesn't concern me is because;

He has never been known for his fitness
He has always appeared slightly overweight
His game does not resolve around running like a mad man

His game has, and always will be his intelligence in and around the box and being able to score goals and set up for others. Something he will still be capabake of.

Although he has not played games recently he will still be training and eating like an athlete 5 times a week. He has not been on a bender since may and hasn't touched a ball since.

Couple of games for match sharpness, even at that I would think he would be fine.