O'Brien, 31, has a year left on his current contract at the Reebok and wants to move in order to gain first team football - and Blackpool boss Ian Holloway is planning a move for the centre-back.
Holloway finally kicked off his summer recruitment drive on Wednesday after signing Craig Cathcart, Ludovic Sylvestre, Malaury Martin and Elliot Grandin.
He wants to sign an additional six players before the end of the transfer window and sees O'Brien as the man to add some Premier League experience to his side.
And although Leeds are still favourites to sign O'Brien, Holloway hopes the lure of the Premier League could lure the defender to Bloomfield Road.