Here are some general tips that may help solve problems like this. In my FIFA 10, there were a few times where there was no grass. It happened when I was changing mowing patterns. However, the grass wasn't gray like in that picture, instead black with glitchy colors.
One thing that seemed to solve the problem was when I didn't turn ENBSERIES on in-game until the game loaded. so, sometime with ENBSERIES on the match would load with no grass, when i turned it off, the grass would load. (once the game loads with grass, then turn on ENBSERIES with shift-f12) Also if you are have dual GPUs, make sure you go to task manager and check the boxes for BOTH CPU 0 and CPU 1.
Finally, when you are importing a stadium patch, don't overwrite another stadium. Make sure when you import the patch, it shows up as Green instead of Red. If it shows up as red, then don't install the patch as it could have graphical problems like the grass problem. go to stadiums and change the ID of the stadium that has the same stadium id as the patch to an empty slot, then import the patch again and create the stadium fully in a new zdata.