While Hansen believes that it is too early to write off the English champions, the Match of the Day pundit believes that there are parallels with Liverpool's demise in the 1990s.
"It is too early to say we are now witnessing the end of the empire at Old Trafford, but alarm bells are ringing and there are clear similarities between the United of 2013 and the last Liverpool team to win the title back in 1990," Hansen wrote in The Telegraph.
"The Ferguson factor really cannot be overestimated, on and off the pitch. It was a massive element of United's success, particularly in recent seasons."
United take on Shakhtar Donetsk in the Champions League group phase on Wednesday.