Even if he makes no appearances this season, I think having someone respected and professional enough to be looked up to as Captain by the squad is invaluable. Camaraderie and togetherness is absolutely essential to a successful team, and his presence alone could be vital to that.
Nobody knows how this Premier League season is going to go. The less we rock the boat in terms of players who are trustworthy with a good attitude, the better. If he helps keep the team's morale up, he'll be worth more than 7.5m for that alone.