Al Horford making progress; still no timeline

Danny Ainge updates the progress of Al Horford in dealing with his concussion, but still doesn't have a timeline for when he can return.

Horford has been cleared to do some light work with the team after being in the NBA’s concussion protocol program since Nov. 2.

Coach Brad Stevens said Horford is doubtful for Friday night against the Knicks, but hasn’t been ruled out entirely for the game.