IWhen PRECISAR is followed by another verb you don’t need the de. But the following verb will always be in the infinitive. You are saying, I need TO do, TO say, TO eat, TO play ETC. The verb following is always in the infinitive.
Eu preciso correr. (I need to run.)
Ela precisa estudar. (She needs to study.)
Você precisa descansar? (You need to rest.)