Caulker, 26, is without a club after leaving Queens Park Rangers in December but is looking for a fresh start after overcoming the mental health issues related to his addiction problems with alcohol and betting.
Now a teetotaller who hasn't placed a bet for nearly a year, he told ITV: “My goal is to get back to the top - playing for England, although it seems far away from, is something I want to achieve.
“Playing and getting a goal on my England debut was surreal but I made some wrong decisions.
“I want it back, my hunger is there. I look back on that day and want more of that.
“Everyone deserves a second chance, a chance to prove themselves again. I have been there and proved it. It is about proving myself again."