You have to look at the fullback crossing short over the middle. The ball is already on its way deep and Burfict clocks him about 35 yards away from where the ball is thrown. In other words, don’t look at where the ball is thrown, look closer to the line.
Back in the day when I played, I only made those types of hits while blocking defensive players. If a linebacker is crossing to follow a sweep to the other side of the field, he’d better keep his head up and eyes on the O-linemen and not just the running back. I would turn into his path and lay him out. Never got called for a penalty. Just blocking.