Walker, who has taken most of the first-team reps in practice, if he doesn’t start.
Being activated doesn’t mean McCaffrey, who has missed five games with a hamstring injury, will play.
If McCaffrey plays, he is expected to be on a pitch count that likely would limit him to fewer than 30 to 40 snaps.
McCaffrey injured his hamstring in the second quarter of a Week 3 win at Houston.
If Walker starts, it will be his second in the NFL.