The attacking midfielder, who has been without a club after leaving Mersin İdmanyurdu in Turkey, becomes the third player to put pen to paper on a Palace deal today, after Darcy Blake and Yannick Bolaise.
Mortiz said: "I'm really happy to be part of this club, I've played the last five years in Turkey and it's a great opportunity for me to be playing for England. I know Crystal Palace is a great club and I'm really pleased we've come to an agreement."
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