Celtics' Horford enters concussion protocol, out vs. Bulls

BOSTON (AP) The Boston Celtics say center Al Horford will sit out Wednesday night's game against the Chicago Bulls after being placed in the NBA's concussion protocol.

The team says in a statement that Horford reported being hit in the head Monday during practice but did not exhibit any symptoms that evening or during a pre-practice period on Tuesday. But he was removed from practice later Tuesday after showing symptoms of a concussion.

Horford, who signed four-year, $113 million deal with Boston this offseason, has started all three games for the Celtics this season and is averaging 12 points and 5.3 rebounds per game.