Reports have suggested Keane could be on his way out of White Hart Lane in January after failing to become a regular at Spurs.
Redknapp told Sky Sports News: “When he came here I said he was so important to this club.
“When we brought him here it coincided with a terrific run that we had last year as well, when he came I think he gave the place a real lift on and off the field and he’s been the same this year.
“He started the season great and he was in the team, Peter (Crouch) wasn’t in the team.
“Robbie had a great start to the season and then it was difficult, Crouchie got three goals in the Carling Cup at Preston and I left him out on the Saturday and brought Robbie back in, I only rested Robbie for that game.
“Robbie came back with four goals against Burnley and Jermain Defoe got five goals in the game against Wigan, so they’ve all been in great form.
“Crouchie got two last week but Robbie came off the bench last week and had a big impact on the game and so he’s really important to us.”
