McCartney has made 157 appearances for Sunderland

The 25-year-old Northern Ireland defender was hurt in Monday's 2-0 friendly victory over Shelbourne.

McCartney left Tolka Park on crutches after being forced out of the game by a tackle in the 70th minute.

Sunderland's 22-year-old striker Andy Welsh also limped out of the game after suffering an ankle injury.

Sunderland coach Kevin Richardson told the club's website: "There were a few naughty tackles out there but overall it was a good workout.

"It looked a very bad tackle on George, you could tell by the reaction of our bench. It was unnecessary and there were a few words said."

Sunderland coach Pete Friar said: "They will have scans and we will know more when we get the results."