My understanding was that in San Diego, we identified the pool of players from which our OC roster would be drawn. Any player identified as a potential for a pro roster cannot play with any other roster in OC (even if they are not playing with the pro team). So we could have rostered two extra players just in case, but if we did, they would not be able to play with anyone else even if we didn't use them.
At the same time, players identified as part of that pool did not have to actually play with the team in San Diego.
I wanted to roster a few extra players just for insurance, but I didn't want to lock them in because I didn't really think I'd need them, so I wrote down their names in the area for 'support staff' and thought I could argue my case that they were really players if I it came to it. Camille made me write "P" or "S" next to each name and then on the bottom write "9 players, 5 support staff" so that killed that idea.
But if Jeff is correct then what I said is completely irrelevant, because it sounds as though players could have technically been on 2 rosters in San Diego.