Redknapp, who played more than 300 games for the club between 1991 and 2002, told Sky Sports: "They have won one in 10 now and fans will be thinking. They are firmly behind him, though, he manipulates the fans, he gets them how he wants them.
"But there comes a time, if they go out of Europe this week and then lose at Everton, that the fans are swayed and will say that we have to look at him now.
"That team is not really going anywhere. The problem you will get is that will Fernando Torres want to play in the Europa League? I don't think so.
"If they don't get into the top four at the end of this season, it will be a major problem.
"You have huge problems going on behind the scenes with the owners, but it is too easy to blame that. On the pitch the players are not playing well enough, that's a fact."