Per NavyHoops above, that’s the deal - if a mid is ready to be commissioned and is otherwise satisfactory in all areas but is found to be NPQ for one or more unrestricted line communities, the “needs of the Navy” will kick in and they will look around for manpower openings in either restricted line (intel, oceanographic, etc.) or Staff Corps (supply, but usually not the other staff corps such as JAG or Medical).
The Supply Corps is an excellent career path, giving junior officers superb business skills. SC officers, if they stay in, are usually afforded the opportunity for their MBA at the top business schools in the country. They become experts in supply chain management, comptrollership, complex military financial management and other critical systems. There is opportunity for command of major supply centers.
The SC professional network is close-knit and provides a great boost to post-military careers in the business world.
One example I know is Carl Liebert, a USNA grad, SC officer and Navy teammate of David Robinson. He went SC, is currently COO at USAA, was formerly the CEO at Home Depot and EVP at 24 Hour Fitness.
Another is CAPT Bill Dawson, SC, USN (Ret), who had a distinguished Navy and corporate career, and is now the CEO of the USNA Alumni Assn.
If your DS has dreams of command at sea or gaining a URL warfare pin, I am sorry if he is having to face this bump in his life’s journey. He can serve honorably as a “chop,” and will gain a solid professional resumé.