It's definitely weird, but I'm not enough of a
to believe he was truly faking it. Concussions are weird things - you can sometimes take a huge hit and be fine, and sometimes a minor hit ends up causing major damage.
It looks to me like he MIGHT have taken a hit to the side of his head when his helmet hits the second defender. Aside from that, it had to have just hit when he hit the ground. Maybe the first was enough to make him black out for a split second and not be able to control his head when he went to the ground or something. I dunno.