It all boils down to if he wants to come back in his peak, or if he wants to come back in the latter days of his career.
As has been proven elsewhere, there's no magical age where you're past it. It all depends on the player. I read somewhere recently that if Distin had been playing like this 10 years, or so, ago, he'd have been a regular fixture in the French National side.
So, if he came back, the key would be how. Would it be as someone who is well past it but can eek out an extra bob based on sentimentality, or someone who genuinely wants to finish on a high with us. Remember, the PL is arguably the very best league in the world, so playing for any club in this comp requires a certain skill level. We're not talking about Del Piero tearing up the A-league at 76 here!