You might want to look into fur shading technique. This is what I would use for this type of grass, since the shorter the grass is the better the performance (less layers).
Basically it works by layering the same surface multiple times in small increments:
You can also change the horizontal offset to make the grass look bent.
Rocket league is actually using long quads with texture that sways using vertex shader
The trick itself is in the LOD, grass is rendered roughly 20meters ahead and the rest is just flat floor, the thing is, the floor sinks to reveal the close grass and raises gradually as you go further away(until it is at the same height of the grass)
So basically the entire grass field is a few lines and a few rows of long quads let's say 500 long + 500 wide that's 20 meters deep.
The rest is simply flat raised ground.