Sources -- Bucks preparing to be without Giannis Antetokounmpo - ESPN

The Milwaukee Bucks are preparing to be without two-time MVP Giannis Antetokounmpo for the start of their opening round Eastern Conference playoff series against the Indiana Pacers, but are hopeful treatment on his left calf strain will allow him to return sometime later in the series, sources told ESPN on Tuesday.

Antetokounmpo has been undergoing around-the-clock treatment on the calf, sources said.

The third-seeded Bucks open a best-of-seven series against the Indiana Pacers with Game 1 on Sunday in Milwaukee. The Pacers won four of five regular-season games against the Bucks.

Antetokounmpo missed the final three regular-season games after crumpling to the floor with a noncontact injury a week ago against the Boston Celtics.

Antetokounmpo ended the regular season averaging 30.4 points on a career-best 61% shooting with 11.5 rebounds and 6.5 assists. He's the first player in NBA history to average 30 points per game on 60% shooting, according to research by ESPN Stats & Information.