Cardinals quarterback Carson Palmer left the impression that both Johnson (knee) and Andre Ellington (foot) will miss time, according to Kent Somers of the Arizona Republic.
The Cardinals haven't provided an update, but Palmer did say that David Johnson and Kerwyn Williams need to step up. That doesn't necessarily mean Chris Johnson will miss time, as Palmer isn't a doctor and may have just been assuming that at least one of (Chris) Johnson or Andre Ellington won't be ready for Week 13 against the Rams. If neither running back is ready, David Johnson will likely lead the Arizona backfield, though Williams could also have a large role.