Stoke boss Mark Hughes told the club's website: "We wanted to try and add different options to our attacking threat and John will certainly do that. He's someone who if you get him in the right areas will make the most of opportunities that come his way because he's a natural goal-scorer.
"There were several clubs who were interested in taking him on loan and we're delighted that he has chosen to join us."
The Potters have also signed on a permanent deal Stephen Ireland from Aston Villa, and Hughes said: "Stephen is a talented footballer and has shown what he's capable of since he joined us.
"We're delighted to have made his switch a permanent arrangement as it also gives us the opportunity to bring in another player on loan if necessary."
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