The American forward pulled up with an injury in the 21st minute of the Americans' World Cup opener and had to leave the pitch on a stretcher.
The U.S. Soccer Federation would later call the injury a "strained left hamstring." Altidore will get further tests on Tuesday.
Altidore tried to run onto a long ball over the top from Michael Bradley in the 21st minute, racing Ghana's John Boye down the left side of the U.S. attack. He pulled up, clutched at his hamstring and immediately began gesticulating to the training staff before being taken from the field on a stretcher.
He was replaced by Aron Johannsson, but despite the young forward's ability, manager Jurgen Klinsmann will hope the Sunderland man can recover for the remaining group matches. The U.S. coach regularly calls the 24-year-old Altidore a part of the spine of the team. Altidore scored twice for the USA against Nigeria in the final friendly before the World Cup.
When Altidore was substituted, the USA was leading 1-0 thanks to a first-minute goal from Clint Dempsey. Ghana would equalize late through Andre Ayew before John Brooks headed home a late winner.