Opposing fans and media are labeling Dellavedova a dirty player after the Horford incident. I just wanted to share a diagram I threw together and my thoughts after watching the play multiple times:
At this point in the sequence, Horford isn't trying to move away from Dellavedova. They're side by side, with Horford holding his arm pulling him along for a ride as he steps to his left. Unfortunately, Carroll is right in Dellavedova's path, tripping him. When he begins to fall backwards, there is no space between he and Horford, which is why he ended up grazing Horford's right shin with his left armpit. This would mark the first time in human history where a player tried to take out someone's legs with their armpit. And why wasn't there any space between he and Horford? Well, look again at where Horford's left hand is positioned.
Horford's drag down was cheap but not especially "dirty" like an elbow from Mutumbo or Malone. That's usually how the word dirty is used in sports. Based by his elbow afterward (which
was dirty), I don't believe it was his intention to drag Dellavedova across Carroll or that he was even aware it happened. It appeared that he was retaliating over what he believed was an attack on his legs. To me, that's the most logical explanation.