Cason was clearly ahead of the receiver at the start when he first saw the ball.
Even though he ended up a little bit in the trail position, he was really close enough.
He had a pretty good idea where the ball is going to go from the beginning.
This is one instance that the DB has to look for the ball.
Another reason here is that Cason was playing outside technique with safety help in the middle.
He didn't have to worry about the post route, and probably not the skinny post either (look at how far outside the numbers the safety got to.)
Reps for all the videos.