Boston Celtics back-up center Robert Williams III suffered a back contusion after a hard fall during the second quarter of the team's game against the Charlotte Hornets.

Williams attempted a put-back dunk but failed and instead landed on his tailbone. He was immediately assisted by the Celtics' medical staff.

He has been ruled out for the rest of the game.

The severity of the injury has yet to be determined, but updates are expected to be provided within the next couple of hours.

The Celtics are now thin at the center position. Al Horford and Aron Baynes are already dealing with injuries, and if Robert Williams III will miss a significant amount of time, this could force the Celtics to go small ball.

One other option for Boston is to proceed with their signing of Greg Monroe. They were reportedly on the verge of signing him to a 10-day contract when Baynes went down with an ankle sprain, but when the management found out that his injury wasn't that serious, they postponed the signing of Monroe.

They will probably look into that option once again.

Injuries couldn't come at a worse time for the Celtics, as they are currently gunning for one of the top four spots in the East in order for them to gain homecourt advantage.

To make matters worse, the team lost to the Hornets 124-117 despite leading for the most part.