"I think it's a little more serious [than initially believed]," Doc Rivers said before the Clippers' 115-104 win against the Los Angeles Lakers.
The Clippers coach added that the team was uncertain whether Rivers would be out of action for a portion of the postseason.
"We don't know," Doc Rivers said. "I would say it's 50-50."
Austin Rivers injured the hamstring in the second quarter of the Clippers' win over the Washington Wizards on Wednesday night in Los Angeles.
The combo guard is posting the most efficient offensive season of his career, primarily in a reserve role. In 74 games, Rivers is averaging 12 points and 2.8 assists per game, with a true shooting percentage of 54.5.
Rivers, 24, signed a three-year, $35 million contact with the Clippers last summer.
In Rivers' absence, the Clippers would rely on their wing reserves of Jamal Crawford, Paul Pierce, Wes Johnson and Alan Anderson, with backup point guard Raymond Felton likely to see additional minutes at the off-guard position alongside starting point guard Chris Paul.