My 13 year old dog doesn’t seem to want to play tug outdoors anymore, is it too much to expect an older dog to play tug?

I'd get him checked out by a vet or good canine chiropractor. All of my older dogs like the idea of playing tug but the truth is they often have physical deficits and diminished strength that may make the actual tugging part of the game uncomfortable or even painful for them. Even if they seem invested in the game they often have pain later or the next day due to muscle loss and stiffness. My old dog Rush would have done bitework or played tug at any opportunity but his old body would make him pay with pain and stiffness the next day. I had to find other ways of rewarding him or tone the game down by just letting him possess the tug and making a big fuss about him and not actually doing any tugging.

Can you use a very high-value food for the recall training outdoors and IF he shows interest in the tug just give it to him and don't really tug?