When a Jedi is fighting General Grievous, why can't they just use the Force to lift him up and render him helpless?

Since Grievous is not Force sensitive to be able to defend himself, what would prevent a Jedi from levitating Grievous or slamming him into a wall? Why did they bother engaging him in pure lightsaber combat? via /r/StarWars https://ift.tt/2Qw3tJ3