Moving all stadium fields to high quality natural grass surfaces is the easiest decision the NFL can make. 
The players overwhelmingly prefer it and the data is clear that grass is simply safer than artificial turf. 
Its is an issue that has been the near the top of the players' list during my team visits and one I have raised with the NFL. 

While we know there is an investment in making this change, there is a bigger cost to everyone in our business if we keep losing our best players to unnecessary injuries. 

It makes no sense that stadiums can flip over to superior grass surfaces when the World Cup comes, or soccer clubs come to visit for exhibition games in the summer, but inferior artificial surfaces are acceptable for our own players. 

This is worth the investment and it simply needs to change now.