The Boston Celtics have upgraded center Al Horford to questionable prior to tonight's game against the Charlotte Hornets, the team announced Friday.

Horford caught an elbow to the head during Monday night's game against the Atlanta Hawks, as forward Kent Bazemore came down with his elbow after trying to block the big man from behind. The play resulted in a regular foul and wasn't reviewed by officials on the spot, or by the league after the game.

President Danny Ainge noted Horford's injury wasn't as serious as the one sustained last season, where he missed nine games in the early get-go.

Horford is the lone returning starter from last year's group and therefore the most familiar with head coach Brad Stevens' system on both sides of the ball.

The Celtics have been by far the best defensive team in the league, boasting the best defensive efficiency rating by 2.2 points per 100 possessions —  a formidable formula that has allowed this team to win 10 straight games after losing their first two to open up the season.

Horford's pivot-like role on offense has been the X-factor in Stevens' share-the-wealth offensive style, as the big man was one assist shy of a triple-double on Monday with 15 points, 10 rebounds, and nine assists.