The German and English sides have engaged the defender in talks for a possible move from Portugal this winter
Freiburg and Crystal Palace are in advanced talks to sign Ghana international David Addy from Vitoria Guimaraes.
Goal Ghana understands that both clubs are ready to sign the left-back this winter and are battling to seal a deal with the former Ghana Under-20 star, who is eager to leave Portugal.
Victoria Guimaraes have 20 per cent of the rights of the left-back and wants to be compensated financially if the deal goes through.
Porto, who own the largest share of his economic rights (70 per cent) are ready to release the player.
Both clubs watched him over the weekend and the deal might go through before the transfer period ends.