Jaylen Brown in Concussion Protocol After Hard Fall on Head vs. Timberwolves

Boston Celtics swingman Jaylen Brown has entered the NBA's concussion protocol after falling hard on his head following a fast-break dunk Thursday night against the Minnesota Timberwolves.  

Brown laid on the court and was examined by trainers for several minutes after hitting the hardwood at Target Center, but he eventually sat up and walked to the locker room under his own power. 

Jaylen Brown with a Scary Fall

"I probably had one of the better looks [at the fall]," Celtics center Al Horford said, per ESPN.com's Nick Friedell. "I was right there. It was just tough to see. I was just happy that he was able to get up and walk on his own power. That's probably one of the worst falls I've seen."

According to league rules, Brown will not be allowed to return until he shows no signs of concussion-related symptoms, has been evaluated by a physician and has successfully completed the NBA return-to-participation exertion protocol. 

Once those criteria are met, the physician will need to discuss the decision with the director of the NBA's concussion program. 

Brown's absence should open up additional minutes for Marcus Smart and Terry Rozier on the wing as the Celtics continue to make a push for the No. 1 seed in the Eastern Conference. Boston is second in the East, two games behind Toronto. The Celts host the Indiana Pacers on Sunday.