Ferguson admitted the blunder when he was asked a question in relation to his disagreement with his defender over Ferdinand's refusal to wear an anti-racism T-shirt, but he has insisted that the 33-year-old can play at the top level for another "two or three years".
Ferguson told The Sun: "I didn't even realise that his contract was up. You are making me panic!
"We have always adopted that policy of offering one-year contracts, and at 34, I think Rio can play for two or three years.
"He is not as quick as he was but that is not a big issue for me. His experience is important and there is no reason he can't stay on."
It was reported yesterday that Ferdinand may have to take a wage cut if he is to sign a new deal at Old Trafford.