Spurs wouldn't permit him to feature in the FA Cup tie at Everton and are considering recalling the 21-year-old.
"I'm not sure what's happening," Redknapp told the Fulham Chronicle.
"It's up to Tim Sherwood what he wants to do. He likes him an awful lot and has been excellent for us.
"I haven't spoken to Tim for a week or so, but if he wants to take him back I need to know because we need time to try and find somebody else.
"I wouldn't want to leave it until the last minute [of the window]. It's a difficult time of year to find players."
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