Essentially, it [the AFO - Ankle Foot Orthosis] is a decide to help him walk even if his nerves are not responding as normal. This doesn’t mean that the nerves are dead, but simply that they may not be working properly now. They could “wake up” in the future. They could also stay the way they are indefinitely.
For comparison, it’s worth noting that Peyton Manning had similar issues after his neck surgery—a cervical fusion—and he took a whole year off. The nerve damage took months to heal. Manning still has issues with feeling in his fingers and people have said his arm strength is no longer what it used to be.
While that didn’t stop Manning from breaking all manner of NFL records in 2013, it’s unclear what the impact on Smith would be if he has the same issues in his leg. As a linebacker, speed, power and agility are incredibly important. Even a slight loss could make it impossible for him to play at the elite level that he seems capable of when healthy.