While the club's manager Rafa Benitez is a huge admirer of Dost, it does not appear the club want to get involved in the red tape it would take to sign him on a free transfer.
Dost terminated his contract at Sporting after some unsavory incidents involving the club's fans and board.
But there are legal issues that could see Sporting challenge the decision of Dost to terminate his deal.
And Newcastle do not want to get involved. It is expected that FIFA will eventually have a say on how Dost and a few other Sporting players recently terminated their deals.
The club's president Bruno de Carvalho is certainly not going to let so much talent walk away for free without a fight.