Ellis absorbed an inadvertent knee while he was defending guard Manu Ginobli, and left the game with 6:43 remaining in the third quarter before.
He left the AT&T Center on crutches and did not address the media.
“He was kicked or kneed in the right calf,” Mavericks coach Rick Carlisle said, according to The Dallas Morning News. “It’s very sore. But we don’t know the extent of it. We’ll see how he feels [Saturday] and go from there.”
Ellis has not missed a regular season game since the 2011-12 season. Over 73 games this season, he has averaged a team-high 19.1 points, 4.2 assists and 2.4 rebounds.
After the game, owner Mark Cuban wrote on Twitter that he doesn't think referees treat Ellis fairly.
At 45-28, the Mavericks possess the No. 7 seed in the Western Conference. They will play at the Indiana Pacers on Sunday.