ANDER HERRERA admits David de Gea’s future is uncertain at Manchester United. It is thought he will start at centre-back, his preferred role – though he can also play at right-back. Jose Mourinho apparently tested the water with a £69million bid that was rejected by the Ligue 1 side. But the Algerian isnt the only player on their radar, with an audacious swoop on rivals Real Madrid for unhappy midfielder Isco in the works. United could be left to rue that mistake with a host of Europes biggest names in hot pursuit. He is looking at huge rebuild of the squad at the Etihad following the end of this campaign. Keep up to date with ALL the Burnley news, gossip, transfers and goals on our pages plus fixtures, r. Jose Mourinho is also an admirer and could rival Blues or City – who have the second-most expensive defender in history having shelled out £47. es3The 18-year-old has made more saves than any other goalie in Europe's top five leagues this seasonBut Donnarumma has already made more saves than any other keeper in Europes top five leagues this season and many expect him to eventually surpass his idol in terms of overall ability. But it appears the neighbours will have to move fast if they are to land the highly-rated youngster.