Both Gary Neville and Wes Brown was forced off with injuries against the Hammers.
Nemanja Vidic had been ruled out before kick-off with the flu and Rio Ferdinand, John O’Shea and Jonny Evans are still out with injuries.
Fergie is now waiting for an update on the latest problems ahead of the Champions League tie with Wolfsburg on Tuesday.
He said: “We had six defenders missing before the game, Gary Neville has had to come off after half an hour and then of course Wes Brown has had to come off.
“I am hoping Nemanja Vidic will be okay for Wednesday. He missed the game with flu.
“We will probably play with Michael Carrick again. I thought he did very well. He has got the height and got the composure.”
He added: “The injuries in defence are becoming a bit of a headache to us.
“But Carrick stepped in and did very, very well. He’s got the composure and the pace and it was a good performance in the second half.
“We used our experience to get the result.”
