They make contact with other players with less time for anyone to get to full speed. The guys they're hitting aren't generally going in exactly the opposite dir

They make contact with other players with less time for anyone to get to full speed. The guys they're hitting aren't generally going in exactly the opposite direction, the way defenders' targets are. There's probably some truth in this, but as a guard, he has to pull and lead on outside runs occasionally. Plus there's always a chance of getting kneed in the head in a pileup. The risk is far from zero. He may also be asked to play on special teams, where the risk is probably the greatest.