Pardew fears Anita may now miss the December 29 meeting with Arsenal whilst also suggesting Jonas Gutierrez will be out for a few weeks after a knee problem kept him from the United clash.
"I was a bit upset with that tackle," said Pardew.
"I have seen it again and I don't think it was malicious but Valencia has mistimed it badly and unfortunately it might cost us a player.
"I am not sure what is wrong. It is too early to say.
"It is a bang on the ankle. We will have to see whether he will make Arsenal, which would be a loss to us."
He added of Jonas: "He will be missing the next two or three games.
"Gutierrez will have an injection in his knee tomorrow. It is not clearing up and he is not 100%."