INDIANAPOLIS (AP) — Damian Lillard underwent an MRI to determine the severity of his Achilles injury, and the Milwaukee Bucks could be without the star guard for Game 4 of their playoff series against the Indiana Pacers, coach Doc Rivers said Saturday.

Lillard is in a walking boot. He was clearly limping at times during the Bucks’ Game 3 loss at Indiana on Friday. Milwaukee trails Indiana 2-1 ahead of Game 4.

The Lillard situation raises the possibility of the Bucks being without both him and Giannis Antetokounmpo on Sunday. Antetokounmpo has not played in the series while dealing with a calf injury that he suffered late in the regular season.

Rivers said it’s possible that Antetokounmpo gets cleared for Game 4, though stopped well short of indicating that the Bucks were expecting that to happen. He said Antetokounmpo will go through a “hard workout” and from there a determination will be made.

There was some good news Saturday, with Rivers saying Khris Middleton — who finished with a playoff-career high 42 points in Game 3 — came through the game fine, despite dealing with the aftereffects of a sprained right ankle.

Lillard added 28 points and eight assists in Game 3, most coming after he hurt his left knee in the first quarter. He aggravated an Achilles tendon injury late in the fourth.

Milwaukee was 1-8 when Lillard didn’t start a game in the regular season.