I have some decent insight on many of these injuries both orthopedic and neurological due to my job; so I will give my 2 cents on what to expect.
Hurts to what I understand has an SC joint separation, essentially follow the clavicle down to where it meets at the sternum. Numerous ligaments down at this location, so will be hard to guess which one was damaged however this joint is usually harder to injure due to the inherent stability at the sternum. AC joint is much easier to injure due to the opposite, excess mobility in the region.
That being said , SC injuries are more time based to rehab versus exercise performance based --> so although the player and coaches may pretend like he is playing.. fact is he will not be able to speed up a timetable recovery on an injured ligament on the sternum.
This location also doesn't have many muscles to compensate for stabilization, removal of inflammation, so it really is kind of in "no man's land" essentially meaning he has to wait it out and rest without provoking it and causing more irritation at the injured ligament site.
Each time he moves his arm and shoulder blade will most likely cause him pain. To the severity I do not know; however if he does end up playing earlier than 4 weeks; I confidently can say he will not be nearly as effective as a passer and the game plan would be heavy in RB running. I don't think he would RPO and risk further injury to the sternum, especially within the first 2 rounds of playoffs.