Martinez added: “There was a moment against Newcastle when he tracked Andros Townsend back all the way and won the ball back.
“That wasn’t his role, but he sensed danger and reacted. When you do that it is because you say, ‘I know what I am and how important I am for the team’.”
Martinez is without John Stones, Tim Howard and Mo Besic at Stoke. New boy Oumar Niasse could be on the bench.