I don't follow football a lot, but my understanding is that players on the offensive line are a lot less susceptible to this problem. They don't tend to tack other players or collide at high speeds. They're almost right next to the opposing player who needs to be stopped and usually just end up grappling with this person. Contrast this with other positions where the player needs to tackle someone or ends up getting tackled a lot.
Players on the front lines have incredibly high rates of TBI because one of the common methods used by both the O and D lines is to whack the opposing player in the head to disorient them. TBI is greatly influenced by the frequent whacks to the head as well as using one's own head as a weapon - one doesn't need to be knocked out to have a concussion or subject to TBI.