The Oakland Raiders were already down one running back when Darren McFadden suffered a hamstring injury last week against the Redskins. McFadden was questionable coming into this week, but was not able to go. The raiders say he is still day to day and it is a minor injury. McFadden's replacement, Rashad Jennings also suffered a hamstring injury. The injury happened in the second quarter of last nights game and was not able to return.Hamstring injuries can be tricky and minor or not it is a tough injury to come back from. It is unknown how long McFadden or Jennings will be out. The Raiders are going to be careful with both of these players because they don't want to bring them back and aggregate the injury. The Raiders play their division rival, the Kansas City Chiefs this week before having their bye week. It is possible we may not see McFadden or Jennings until after their bye week.If Jennings and McFadden are unable to play this upcoming week expect Marcel Reece to start in their place. When Jennings went down last night Reece received most of the carries. Expect Terrelle Pryor to also scramble out of the backfield as well to create more of a rushing attack.Follow @TheNFLInjuryRpt Looking for fantasy football advice?