Sandro limped off in the first half with what Redknapp thinks is a torn calf muscle while Gallas was replaced after the break.
Redknapp said: "Sandro tore a calf - that will be a long one. Gallas as well, it looks like he's done a calf.
"They will have scans tomorrow (Wednesday) and we will have to see how they are."
But Redknapp says the injuries will not affect his plans not to sign any reinforcements in the January transfer window, adding: "I don't have any targets at the moment that I would go to the chairman and say we should get."