Milwaukee Bucks star Damian Lillard exited in the first quarter of Sunday night's 129-103 Game 4 loss to the Indiana Pacers because of a left lower leg injury.
The preliminary examination of Lillard indicated a possible Achilles tendon injury, a person with knowledge of the situation told The Associated Press.
Lillard is scheduled to undergo an MRI on Monday, when the Bucks are expected to know the severity of the injury, league sources told ESPN's Shams Charania.
"Just being honest, it's not very promising," Bucks coach Doc Rivers said postgame.