A week with no natural sunlight. Less than zero chance. IMHO
Modern pitches are a mix of grass and artificial, they are all constructed with several layers, ensuring rigidity, bounce, irrigation, water retention and drainage. I think on average they need a base depth of 6-8". If they keep airflow and UV lamps I imagine the grass will be ok for 3-5 days, any longer and it may start to suffer. Don't the currently use UV lamps overnight at the moment to force the grass to grow 24hrs a day? Doing this means it's possible to cut the grass before each game removing the top few mm of damage to the blades? Don't see what they're planning will be much different.
Was going to type more but bored myself... Just sign someone FFS, I need something else to think about.