CELTIC right-back Cristian Gamboa could be facing a lengthy spell out of action after tearing a thigh muscle on international duty.
The defender had been on international duty for Costa Rica in the Gold Cup.
But Gamboa, bought from West Brom for £1million last summer, had to be carried off during the 1-1 Group Stage draw with Canada in Houston after sustaining the injury.
The Costa Rican FA have already flown him back to his homeland to be examined by specialists.
Team Doctor Alejandro Ramirez said: “Cristian has a first-degree tear in the right biceps femoris.
“If he stayed with the squad, he would run the risk of his injury getting worse.
“So, we decided to withdraw him from the tournament and send him to Costa Rica for treatment.
“He will rest and then get two weeks of therapy.”
The Hoops medical staff will be anxious to discover the timescale of the absence of the attacking defender who made 21 appearances last season.
If he is out for a considerable amount of time, it will leave Brendan Rodgers with only youngster Anthony Ralston as back-up to Mikael Lustig.
