Either Damien Williams or LeSean McCoy has been the Chiefs’ featured back on 119 of 129 plays this season, or 92 percent. Neither was participating in the early portion of practice on Wednesday because of injuries. Darrel Williams and rookie Darwin Thompson, who between them have 10 plays this season, would be in line to get the work on Sunday against the Ravens. Thompson, a sixth-round draft pick, was impressive in training camp and the preseason and looked like he would get a portion of the work in the regular season until the Chiefs signed McCoy. Coach Andy Reid said he wants to make sure Thompson knows his assignments as a pass blocker before he gets a lot of playing time. “As long as I feel like he knows what he’s doing, I’m good with it,’’ Reid said. “He’ll stick it up in there and hit you. It’s just a matter of seeing it. He’s young so he hasn’t seen everything there is to see. He’s getting there. I feel comfortable with him in there.’’