Preston chairman Derek Shaw told the club's official website: "We made Aberdeen an offer earlier this month which was not accepted.
"I understand that Aberdeen have agreed a fee for two of their players with another Championship club, however Michael has chosen to come to Preston and we are delighted with that.
"Ideally we would like to agree compensation with Aberdeen in the January transfer window and Michael can start his Preston North End career sooner rather than later, however if that doesn't happen then Michael will be our player in time for pre-season in the 2008/09 campaign."
