Low grade is 1 week, mid grade is 3-4 weeks depending on MRI (think partial tears of ligaments), high grade requires surgery complete tears, labrum injury, could be a lot.
http://www.drstaub.com/shoulder-separations/
I had grade 1 in HS and two years afterwards I need to have full capsular shift down because even though it was a grade 1 the ligaments never snapped back to pre injury condition, they stayed stretched.