I think that's just them trying to run a different option from the personnel grouping.
They want him out there for the threat, but when the play is called for someone else, he has to at least make an effort.
The play you reference, he basically motioned too far from the end of the line, and Chase just made an inside move.
That motion is basically trying to move defensive players away from the other [run] side.
He is probably more inclined to take that motion and release as a short, outside target most other times.