Tottenham Hotspur do not know whether injured defender Jonathan Woodgate will return from his latest lay-off before the end of the season.
Woodgate, 29, has made just three Premier League appearances this season and none at all since November after struggling to shake off a long-running groin problem.
"He's got three weeks of treatment to go," said Redknapp after revealing the defender has travelled to America for further treatment.
"We didn't feel we were getting where we wanted to get.
"He went to see someone who he really believes in, who got him fit before. You have to take that chance.
"Hopefully he'll come back at the end of the month and feels it has worked. If he has then he'll be back playing, if it hasn't worked we're struggling a bit with it."
Woodgate has made 64 appearances for the north London club since joining them in a £7million deal from Middlesbrough two years ago.