On two separate incidents in two separate games, two #1 running backs for two separate teams suffered concussions and were forced to leave the game. The severity of the injuries isn't known yet, but both Rashard Jennings and Le'Veon Bell may be affected for the remainder of the games on their schedules. In Rashard Jennings' case, it was caused by an accidental hit by a Cowboys defensive player when he took a knee to the back of the helmet at the the end of the play. However, the Le'Veon Bell concussion looked more greusome, as two spearing Ravens defense backs collided head-first almost at the same time with Bell's head leaving him motionless and laying on the field without a helmet for some time. Both running backs eventually had to be assisted off the field, and looked very woozy on the sidelines.
Although both appeared to be injuries suffered in the heat of play, these are still unfortunate events, and may have an impact on your fantasy teams as you move into the playoff weeks. The chances of either of these two running backs playing in their next game, based on the visual severity of the injuries, seems low so you should already be preparing contingency plans in advance in case they miss a game or even more. Jonathan Dwyer would be the fill-in RB for the Steelers if Bell is out, and doesn't have much upside for fantasy leagues. Darren McFadden who recently returned from an injury of his own would most likely resume leading RB duties for the Raiders, if Jennings had to miss time, with Marcel Reece potentially being worked into the mix as well.
Hopefully the NFL takes the Le'Veon Bill injury especially seriously, and even starts issuing harsher penalties to players for these types of dangerous hits to the head. More news and updates to come shortly so stay tuned.