Leonard rolled his ankle late in the fourth quarter while attempting to make a block, though the player subsequently had seemed hopeful there would be no lay-off.
The small forward's absence at Chase Center alongside fellow key man Paul George, however, is a blow for the Clippers, with no time frame set for his return.
"[He] woke up with some soreness in his ankle," Lue stated when asked on a prognosis for Leonard's recovery.
"It was a little more than we thought. But he's okay, [he's] feeling better, getting better. We don't know a timetable."
Despite defeat, the Clippers still sit just inside the top six of the Western Conference, having posted eight wins and four losses in November so far.