The 28-year-old, named on Tuesday in England's 23-man squad for the World Cup, appears set to leave the Premier League champions this summer and has been linked with a number of clubs, notably Spurs and Manchester United. Arsenal are also said to be in the running for his signature.
But Redknapp, Cole's old manager at West Ham, said he would not be heading to White Hart Lane.
"It looks to me someone's going to make a great free transfer, if he doesn't stay at Chelsea," Redknapp told BBC Radio 5 Live.
"I genuinely don't know who that is. I don't think it's going to be Tottenham.
"I've got a feeling, I may be wrong, that he's already agreed a deal with someone, and it's not Tottenham.
"I'm not saying if he hadn't agreed a deal with someone and he was available and didn't stay at Chelsea that we wouldn't be interested.
"I'm a big fan of Joe's, but the feedback we've had is that he might well have already done something."
Cole struggled with injury for large parts of last season and on his return to fitness was often overlooked by Blues boss Carlo Ancelotti.