Hatem Ben Arfa will fly back from Newcastle's US tour after being taken to hospital during the 0-0 draw with Sporting Kansas City.
The Frenchman was carried off the field on a stretcher after a challenge and was taken for an X-ray on his left ankle.
Ben Arfa missed all but four games of last season with a double leg fracture.
A club statement said: "Hatem Ben Arfa sustained an injury to his left ankle in a tackle during the club's friendly against Sporting Kansas on Wednesday evening and went to a local hospital for a precautionary X-ray.
"Consequently he will be leaving the club's US tour and the injury will be reassessed over the next 48 hours."