Bates told Yorkshire Radio: "Before they got beat at Liverpool on Wednesday they hadn't conceded for a number of games.
"You can never tell what will happen on Saturday, though. Things happen in cup matches.
"As with the Man Utd game, we'll go there expecting a good game, hopefully not picking up any injuries, and we'll look to give a good account of ourselves. If we do that you never know what might happen.
"If we don't get anything we'll get on with our league campaign."