There's no mention of a neck injury for Jayden Reed in the wiki. The only injury history noted is a collarbone break in 2025 (from the Jayden Reed page). Nothing about any neck issue in 2026.
It's possible this is a recent report that hasn't been added to the wiki yet, or a minor day-to-day listing that didn't make the cut. If you can share where you heard about it, I can dig further — but based on what's in the system, Reed's primary 2026 story is about his expanded role with Romeo Doubs and Dontayvion Wicks out of town, not any injury concern.