As a phrasal verb, being grounded out can be the same as being "grounded". That is, to be restricted to your home, wheter it is because it´s ill or as a punishment (with the loss of some privileges, etc), generally meted out by one´s parents.
In the following case, the person is a 27 year-old, so it certainly it wasn´t the said punishment, perhaps he had a broken leg, etc. Fred HerschI was grounded out there for a week. The day after 9/11, the residents and staff put together an impromptu and very heartfelt ceremony in the garden as a memorial to those who died, and to pray for peace in the world. It felt odd being in a bucolic setting, surrounded by elks and bunnies, when my home was under attack, but I was helpless. I wasn’t sure whether to be relieved to have missed it or that I wanted to have been there.http://jazztimes.com/articles/17199-fiv ... ct-on-9-11