Transfer negotiations are ongoing between Paris SG and Porto over Diogo Costa, the highly-rated goalkeeper - with multiple reliable sources confirming the story. The clubs are believed to be some way apart on valuation, but dialogue is open as they look to strike a deal ahead of the run-in. Unconfirmed reports suggest both sides are hopeful of finding a resolution in the coming days - with other interested clubs said to be circling. While Paris SG and Porto continue talks, no breakthrough has been reported. Aston Villa and Galatasaray reportedly may still have an interest, but currently the focus is on getting this deal across the line. Paris SG's back line has been a real strength this season, conceding just 0.82 goals per game (27 in 33). Diogo Costa would be expected to slot into that unit and hold his own in an already solid setup. Reports suggest Paris SG are monitoring Federico Valverde and Maghnes Akliouche whereas Porto have not been associated with other players at this stage. Can't get enough Paris SG transfer rumours? Follow @PlayerSwitchCom on Twitter for the latest transfer news as it happens.