Originally Posted by Bluestang
You would want the TE running a post in order to put the safety in conflict to decide to cover the post or the corner.
Either way it's a good combination to beat a 2 man-under defense.
Not necesarrily, cuz then you might just run the TE/RB into the other safety. If you run him down the seam you either pull the play side safety away from the corner route, or that safety stays on the corner forcing the backside safety to come all the way over. A post would work if the ball is thrown on time, a seam is better cuz it puts more pressure on the playside safety but at the same time there's less of a chance of the backside safety being able to get over and help.
Of course if you're facing a tampa 2 with a good MLB he'd be able to take away the seam and post anyway (or at least give a smaller window for the QB to throw into).