The striker is on-loan at Toon from the Rs.
Redknapp explained: "Remy wants to play Champions League football next season, so they tell me. The chances of us keeping him are not great if he's got a buy-out clause.
"He's done well at Newcastle, and one or two other big clubs are trying to get him, so there's every chance he will go.
"I chased him at Tottenham, and I knew he would do well.
"He's a scorer, and with the right team pushing to get in the top four, he's capable of getting 20 goals. If I say he's worth £20m, and his buy-out clause is £10m or whatever, then it's difficult."
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