Seeing it again, the low hit on Tannehill, yes it should have been flagged, a 15 yd penalty too, but more importantly it looks like a direct strike/bang right onto the knee cap (and not the ligaments etc). I see it as a deep bone bruise or a sprained knee at worst, and he would be back in a week or so. Tough to say, but not seeing the major year ending and 8 month recovery injury here.