
What made that PI, in the eyes of the official AND Pereira was Sergio not playing the ball(read:faceguarding. Which isn't even a penalty anymore). So you claim that Sergio impeded the WR from coming back from an underthrown ball. Not a planned come backer, since Fitzpatrick was about to get pancaked by someone, and just chucked it...but, if Sergio WAS facing the ball and impeding the WR then the WR coming back to the ball and making contact with Sergio...it would have been offensive PI....so the only difference being whether or not Sergio was looking back at the ball...and since there is NO LONGER FACEGUARDING as a penalty, that wasn't PI.
Leaving out, btw, that the WR had Brown in a deathgrip bearhug....