North End were recently linked with a move for Newcastle defender Mike Williamson but he decided to see out the remainder of his contract in the north east to fight for his place.
Pretson are now reportedly interested in taking Bournemouth midfielder Shaun Macdonald on loan. Coventry are also looking at taking the midfielder on a loan deal.
Grayson already has five loan players in his squad which is the maximum he can use on a matchday. If Macdonald was signed then one loanee would have to sit out on match day.