I actually had a tutorial and a link to a script to do this in after effects.
The tutorial had an semi pro skateboarder sportsman on a green screen .
The after effects artist keyed the silhouette of the man and used a script to crop the layer to the silhouette across all frames and also center the pivot point of the layer to the geometric center of the silhouette across frames.
And then he attached a null object to that moving center point to show us it has true position data across the frames without tracking.
I always disliked that tutorial but I need it now and cannot find it.