Carroll and Tottenham fullback Benoit Assou-Ekotto have joined the Rs on-loan.
"He's a player I fully expect to go to the very top of the game - he's a future England international," said Redknapp.
"I played him at Spurs in Europe and he was fantastic for me. He's got all the attributes to be a top, top player.
"He can pass, he can create, he can score goals - he's a fantastic player and I'm confident he'll flourish here for us."
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