Guidetti is on-loan at Celtic, which face Inter in the Europa League.
"He had a lot of injuries when he was with me but I hope he has now recovered from what happened. John can go to the very top if his physical condition stays OK.
"He is a fantastic player and a quality striker. He is strong and scores a lot of goals.
"I hope John does not come back to haunt me but I hope that he plays in these two games. I want him to score goals and have a lot of success in his career - but not against Inter Milan."
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