INDIANAPOLIS (AP) — Damian Lillard underwent an MRI to determine the severity of his Achilles tendon 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 greeted reporters as he strolled through an Indianapolis hotel wearing a walking boot on his right foot, but he did not take questions. Officially, Lillard and two-time league MVP Giannis Antetokounmpo are both listed as doubtful for Sunday.

“We don’t know yet. Not looking great but we don’t know yet,” Rivers said when asked about Lillard’s status for Sunday. “They’re going to give us the test results soon, so we should know a little later today.”

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

Lillard was clearly limping at times during the Bucks’ 121-118 overtime loss at Indiana on Friday night. The eight-time All-Star twisted his left knee when Pacers forward Pascal Siakam stepped on his foot in the first quarter. He stayed on the ground briefly before going to the locker room.