For a number of years, players have been taught to "take a knee" when they are having any difficulty. They teach them NOT to try and get to the sideline because of the problems with getting off the field and getting someone back on the field.

Sure, the one time seemed to highlight something that "looked" bad. But as some have pointed out, if he felt gassed or felt slightly injured, he looked over to the sideline and went down. A bad look, but not anything to be whining about IMHO.