Currently on-loan at Sheffield Wednesday, Marshall is off contract at Stoke in June.
He told the Yorkshire Post: "You have to bide your time at a club like Stoke. You have to look at the players who are in front of you - players like Jermaine Pennant who have won European Cup medals. It's my last year at Stoke and, yes, I am playing for my future. But I'm getting minutes on the pitch at Wednesday and a lot of experience playing in front of big crowds which is benefitting me.
"I have had a chat with Tony Pulis (Stoke's manager) and he just wants me to get game time rather than sitting on the bench. The way he was talking I will hopefully be in his future plans. You just have to keep working hard and see what happens."