X-rays can show bulging, and sometimes herniated, discs. However only and MRI can show the extent and if they are pressing on any nerves. It was an X-ray that first showed up that I at least had 3 bulging discs from an old stress fracture. MRI's later confirmed they were herniated and pressing up against nerves. In Zac's case, his injury seems to be more severe then injured discs if he has fractured vertebrae. In the long term, a severely sprained neck or fractured vertebrae (broken neck) can be easier to recover from compared to chronic disc problems, however it is usually recommended that the person give up any high impact sports that puts their neck at risk. Here is hoping that Zac makes a full recovery and will be successful outside of football it that is the diagnosis.
What amazes me about Scott was how quickly he must have realized something was very wrong with Zac. In most instances, the guy would have gotten right up, not being malicious, but just not thinking about it. Heck, he could have thought Zac was just trying to be a jerk by not getting up quick enough, as those of us that have ever played on offense know that defensive guys will do time to time just to rub in the fact they just made a tackle on you. For Scott to have that much awareness speaks volumes of the kid.