Mickael Pietrus received some good news on day after he was taken off the floor in a stretcher. (Matt Slocum/AP)

Celtics forward Mickael Pietrus was cleared to return to Boston on Saturday, one day after suffering a head injury in a frightening fall during a game in Philadelphia.

Pietrus was driving to the basket when he collided with 76ers point guard Lou Williams and crashed to the floor, landing hard on his lower back and immediately clutching his neck. He was seen convulsing, vomiting and spitting up blood immediately after the fall, and was removed from the arena on a stretcher.

According to the Celtics, Pietrus sustained a concussion, but the MRI, CT scan and X-ray taken at a nearby hospital on Friday were all negative. Pietrus spent the night in a Philadelphia hotel, and on Saturday, he posted some more positive news on Twitter.

Wanna thank the NBA Family especially CelticsNation(fans staff n teammates) n the fans around the world 4 their support.

— Mickael Pietrus (@MickaelPietrus) March 24, 2012

Medical staff in Philly was great im feeling much better n will keep u posted on my recovery.Hope 2 b back with my C’s soon #Blessed

— Mickael Pietrus (@MickaelPietrus) March 24, 2012

Pietrus is still a long way from returning to the floor, however. He must undergo a series of tests in accordance with the NBA Concussion Program.

“It’s always tough when you see your fellow brother, NBA player — regardless of who it is,” Celtics guard Paul Pierce said after Friday’s game. “When you catch somebody laying there on the ground and not moving and you get carried off the floor on a stretcher, it’s tough.

“Those are things that can be career-ending type of things. We just hope he’s able to make a speedy recovery.”

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