North End have been linked with Wigan Athletic striker Kyle Joseph, with them one of a number of clubs interested in the 19-year-old.
Joseph is out of contract this summer but would a youth compensation fee would have to be paid because of his age.
At this stage, Swansea look favourites to sign him, with Tottenham and Rangers other clubs reported to be in the running.
Elsewhere, most clubs have put their retained lists in, Cardiff releasing five first-team players yesterday.
Here is a round-up of the latest transfer talk from the Championship.
1. Sheffield United release quartet
Phil Jagielka, John Lundstrum, Simon Moore and Jack Rodwell have been released by Sheffield United as they start planning for life in the Championship. (Official website) Photo: Press Association
2. Goalkeeper in demand
Freddie Woodman has left the door open to returning to Swansea next season after helping them to the play-off final. The goalkeeper is on loan from Newcastle. (Football league World) Photo: Press Association
3. Bristol City join Middlesbrough in striker hunt
Rotherham striker Michael Smith is being eyed by Bristol City. Smith is already on Middlesbrough's wanted list. (Bristol Post) Photo: JPIMedia
4. No Oakwell move for USA striker
Barnsley have decided against turning striker Daryl Dike's loan from Orlando into a permanent move. (Barnsley Chronicle) Photo: Press Association