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The Boston Celtics will not have their leader available for the rest of the playoffs as the Eastern Conference Finals shifts back to Cleveland for Sunday's Game 3.

The Celtics announced Saturday that Isaiah Thomas will miss the remainder of the postseason after the "re-aggravation of a right femoral-acetabular impingement with labral tear." He initially suffered the injury on March 15, aggravated it in Game 6 of Boston's last series against the Washington Wizards and further damaged it in Game 2 of the Eastern Conference Finals against the Cleveland Cavaliers.

Celtics general manager Danny Ainge tweeted his feelings on the injury:

Chris Mannix of The Vertical previously called the injury "significant" and noted there were doubts within the Celtics organization regarding whether Thomas could play Game 7 of the last round, let alone continue in this series after he left Game 2 early.

This is a critical blow for the Celtics, considering the All-NBA Second Team performer averaged 28.9 points and 5.9 assists per game behind 37.9 percent shooting from three-point range this season. He was a primary reason the Celtics finished with the No. 1 seed in the Eastern Conference.

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Thomas also showed his ability to take over critical moments in the postseason with 53 points in an overtime victory in Game 2 of Boston's second-round series against the Wizards.

Things look even more dire now for the Celtics after they lost Game 1 against Cleveland by 13 in a contest that wasn't as close as the final score indicated and Game 2 by a whopping 44.

Boston has overcome a 2-0 deficit once during this playoffs after dropping its first two contests at home in the first round against the Chicago Bulls, but this a different story. It is difficult to envision anything but a victory for LeBron James and the defending champions without Thomas on the floor.