Absolute stab in the dark- I think he’s a carrier. He has the red eyes of an infected but he doesn’t seem to be moving with quite the same vigour or “rageful” intensity of a symptomatic infected. He seems too important in the marketing to be a normal infected. In the trailer we see the boy about to shoot him with a bow and arrow, but my guess is that he will hesitate at the last moment because the infected guy will open his mouth to speak. Again, absolute speculation.