While Alex Ferguson may no longer be a threat to the deal, another Scotsman, namely Blackburn boss Graham Souness, will be ready to do all he can to prevent Duff moving to his former club.
Though it is clear that any deal for Duff is fraught with danger and has the potential for disappointment, Aldridge insists that Gerard Houllier must pull out all the stops in a bid to secure the transfer.
Aldridge, speaking in the Liverpool Echo, said: "He is a player I have been a big admirer of for the last two or three years.
"If Duff does arrive at Anfield this summer it will be the club's best signing for some time."