USC senior point guard Jio Fontan suffered a potentially serious left knee injury during the second quarter of the Trojans' eventual 81-70 loss to Mogi das Cruzes in Sao Paulo on Tuesday.
X-rays on the knee were negative, a team spokesperson said, but Fontan will undergo an MRI exam Wednesday. As of now, it's being called a sprain.
"I'm always worried about any injury," O'Neill said by phone from Sao Paulo late Tuesday. "But we won't know anything until tomorrow."
USC was up by six at the time Fontan went out of the game, but the Trojans quickly fell behind without their captain and senior leader. Forward Aaron Fuller also missed the game with an illness, so USC was forced to play walk-on Eric Strangis extensive minutes and work newcomers Greg Allen, Alexis Moore and Byron Wesley into the rotation.
O'Neill said they were in a "little over their heads."
Sophomore guard Maurice Jones led the team with 17 points and eight rebounds and center Dewayne Dedmon had his best game yet with 15 points, five rebounds and three blocks. Forward Garrett Jackson added 12 points and six rebounds and Fontan had eight points at the time of his injury.
"We actually played well, against another good team," O'Neill said. "Our guys did a great job."
USC will travel from Sao Paulo to Rio de Janeiro Wednesday and then play its final game of the trip on Friday in Rio. The Trojans had planned on playing a game Wednesday or Thursday in one of the two cities, but those plans have been scrapped.