Don't overrate the long-term viability of a player.
If you enter Week 9 sitting at 3-5 or 4-4 with concerns about making the playoffs, you shouldn't be looking too far down the road. If you don't win now, late-season matchup could be rendered meaningless.
Kenyan Drake wasn't a top-40 fantasy running back during his eight weeks with the Miami Dolphins this season, yet he might be the top waiver-wire pickup. The Arizona Cardinals acquired Drake just days before hosting the San Francisco 49ers on Thursday night. Both David Johnson (ankle) and Chase Edmonds (hamstring) could be out, so Drake may be walking right into a better and more significant role than he had in Miami.