"I had four months out injured last season, so it hasn't really affected me," he said. "The boss will know when I'm tired and I'm not. On the pitch you don't think about it."
Walcott also missed the Under-21 tournament with a shoulder injury two years ago in Holland when England were knocked out on penalties after a marathon shoot-out.
He said: "I remember Stuart calling me and telling me to go and have the operation because there would be plenty more tournaments to come. I wouldn't say I owed them, I just wanted to be here."