Argentinian midfielder Faurlin is to undergo a scan to determine the extent of the knee injury he suffered against Derby on Saturday.
Redknapp was already without Nedum Onuoha, Niko Kranjcar, Tom Carroll, Gary O'Neil and Bobby Zamora and now fears Faurlin faces a long spell on the sidelines.
He told the club website: "He's done his knee and it doesn't look great.
"His injury is a real blow for us. It looks really nasty but we're keeping our fingers crossed that it's not as bad as we fear.
"We'll have to look into our options. People keep telling me we've got a big squad but that's not the case.
"All of a sudden we've got some serious injuries to first-choice players."