The former Manchester City captain announced his international retirement from England last week.
Now hanging up the boots altogether is under consideration, as Walker explained on the Overlap: "I’m 36 in May, but I’m feeling good. It takes longer to recover; I can tell you that. One million percent. And probably now I'm probably doing a lot more defending than I've ever done in my career, but I feel good.
"It's more for me upstairs and you fight your little battles in your head if you can keep doing it. I don't want to tarnish what I've done but I also have a level of respect for myself that I'll do it on my terms.
"I'm not letting outside noise reflect what I want to do as a footballer because it's a short career and people don't understand that."
He continued: "I don’t know if I’ll continue playing for a few more years. I feel once that time in my head comes where I'm done, I'd have to be true to myself. Leave the game before the game leaves you."