Nia Jax noted on Instagram Stories that she is currently at home rehabbing. She did not provide details on what kind of injury or if she will need to take an extended amount of time off from the road.
This probably explains why she was not featured on this week's episode of Monday Night Raw. She was also not at the weekend live events and she was not at last week's Raw. Jax is currently not penciled in for anything at SummerSlam.
The only thing we know is that she's had back issues since 2014 when she was involved in a car accident caused by a drunk driver. Whatever the injury is, hopefully, she will have a speedy recovery.