"It's difficult for us to play friendly games because of the expectation on us," said Ferguson.
"Even if we lose a friendly there's criticism, from the press, our own fans, our own staff. We can't go into any game not wanting to win. That will be the case against the Revolution."
He added: "We're maybe a little bit short but we have a good squad with us and we respect the Revolution and the job Steve Nicol has done."