I think they had to save face in January by not selling a player (they maybe couldn't / didn't want to replace) to a relegation rival. Now the player has handed in a 2nd transfer request with all the summer transfer window in front of them, and considering we're no longer rivals, I imagine PL would get him - assuming no takeover is imminent.
Lambert could probably now offer more than the £1M allowance that was reportedly provided in Jan which may help!