Fergie waiting for Tevez to return from Mars
Tevez was due to return to Manchester later on Friday after playing for Argentina in their 6-1 World Cup qualifying defeat at high altitude in Bolivia in midweek.
"We are waiting on Tevez coming back. I think Mars is where he was playing," joked Ferguson at a news conference. "What a journey he has had.
"The extra day's rest, playing Sunday, helps in that respect but we are unsure of our strikers.
"If Tevez is okay that gives us one striker and then we have to choose someone else."
"If we had picked up more injuries in the internationals we would have been in a difficult position. Now, with the extra day's rest, I'm relatively confident we can get a fit team out." After defeats by Liverpool and Fulham, United will kick off against Villa in second place if the Anfield club avoid defeat at Fulham on Saturday.
The prospect of a hat-trick of league defeats for the first time since December 2001 does not concern Ferguson.
"The players have gone away, met different colleagues, played a different type of football," he said.
"The break came along at the right time for us.
"It doesn't matter how we got here. All we have to do now is know we can trust these players and they can trust each other.
"With that ability and experience we have got in run-ins we expect them to kick on. It doesn't matter what happened in previous games."