Redknapp has warned Tottenham skipper King that he must play at least 20 games this season or risk the axe next summer.
"He has to play this year. I can't go to the chairman and say: 'Give Ledley a contract,' if he has only played two games because he isn't going to do that.
"This is Ledley's big year, he's got to play 20 games or so, really. Ledley needs to put some games in this year to get another contract."