The injury-plagued defender picked up the problem in a training session on Friday.
"Ledley came out for a little jog and tore his hamstring," said Redknapp. "He has had a scan but I have not got the results yet. It means the only options I have are [Michael] Dawson, [Sebastien] Bassong and [Younes] Kaboul. There is no one else."
Redknapp's shortage of defenders means that he is likely to step up his pursuit of Blackburn Rovers captain Christopher Samba.
The White Hart Lane club have also been linked with a move for Aston Villa centre-back James Collins.