The Bolton Wanderers centre-back is edging closer to a move to Stamford Bridge following weeks of negotiations with the former Premier League champions.
While questions have been raised over the delay of the deal, Redknapp has hinted that Spurs have enough defenders in the North London squad.
"I haven't got too many names that I can really push [to chairman Daniel Levy]," Redknapp told talkSPORT. "I like Cahill. Cahill is a good player, but [Michael] Dawson is a good player, [Ledley] King is a good player, [William] Gallas is a good player, [Younes] Kaboul has been a top player this season and I've got [Sebastien] Bassong.
"It's a difficult one. I've chased him for two years and I do like him. I think he's a top-class centre-half."
Spurs currently sit third in the Premier League table, level on points with holders Manchester United.