Boston’s already-thin frontcourt just got even thinner.

Forward Robert Williams will be out for at least three more weeks due to a bone edema in his left hip, the Celtics announced Monday. Williams missed the last three games with the nagging ailment.

Here’s the update from the Celtics:

With Williams on the shelf for roughly a month, the Celtics will be forced to lean even more heavily on centers Enes Kanter and Daniel Theis. Whether there now is a path for Tacko Fall to see more minutes remains to be seen, but Vincent Poirier figures to be first in line for an uptick in usage.

Williams is averaging 3.9 points, 4.6 rebounds and 1.1 blocks per game.

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