"I promised my family at this World Cup that this next four years is really important to me and I want to give everything I've got to get as close as I can to that set-up (England)," Steele told the club's official website.
"I've had to think about my career and moving on. Whoever even mentions money to me as being a reason is a foolish man because I can assure you it's nothing to do with that."
On his departure from Barnsley, Steele added: "It was the hardest decision in football that I've ever had to make.
"There were times when I thought I'd be here forever and I really did want to break all the records and play longer than anyone else.
"That made it more emotional for me to leave. Leaving is huge and I want to thank all of the fans for being so good with me from the start."
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