Josh Smith, at 6’9 225, and Al Horford, at 6’10 240, are both excellent defensive players. But neither has the size to handle traditional centers like Dwight Howard.
In the regular season, where very few teams have seven-footers with low-post games, this weakness can be hidden. Atlanta, because they started two athletic 6’9+ forwards who each averaged over a block a game, had the 13th rated defense in the league last season.
But when they faced Dwight Howard’s Magic in the second round, they were in a lot of trouble. Howard shot a preposterous 27-32 from the field as Orlando demolished the Hawks in a four-game sweep. Their average margin of victory in the series was over 30 points.