He had Spartak Moscow goalie Pletikosa on loan last season.
He only featured once in the Carling Cup, with Heurelho Gomes the No1 at Spurs. But Redknapp told the Scottish Sun: "Stipe's a great lad and a very good keeper.
"He is very experienced and was unlucky not to play more games, but his lack of action was certainly nothing to do with his ability or attitude.
"I liked him very much and he was a top class boy.
"Stipe could do a great job for Celtic. He's got loads of international caps and would be more than good enough."