It is not. If Lattimore is injured, all it means is they'll move Taylor to the boundary (where he excels) or leave Taylor in the slot (he's had a hot start to the year there) and put Kool-Aid or Payton on the boundary with a Safety over the top.
The blessing in disguise is Lattimore has missed 17 games the last two seasons. DA's adjustment for Lattimore being out of the lineup at this point is probably perfected.