Christian McCaffrey (hamstring) will not practice on Wednesday.

49ers coach Kyle Shanahan said more than a week ago that McCaffrey has a “mild” hamstring strain. Hamstring strains can be finicky. If Kaelon Black is available, add him immediately. McCaffrey still has a chance to play in Week 9 against the Raiders’ soft run defense, but he is ever so slightly in the questionable column at this time.