George was considered a lock to make the final 12-man roster for the World Cup of Basketball that starts later this month in Spain.
“Thanks everybody for the love and support,” he wrote on Twitter. “I’ll be ok and be back better than ever!!! Love y’all!!”
The Americans planned to reduce the 20-play pool to 14 or 15 players Saturday, but put off those plans after George’s injury.
“Everything’s on hold right and it should be,” Krzyzewski said. “It would be so inappropriate for us to talk about anything else when there’s a serious injury like this.”
The defending champion U.S. team had already been weakened by player losses. Forwards Kevin Love, Blake Griffin, LaMarcus Aldridge and NBA Finals MVP Kawhi Leonard had all pulled out in recent weeks.