A well isolation unit has an inlet, an outlet, at least one flow pathway connected between the inlet and the outlet, and at least one bleed-off manifold connected between the inlet and the outlet. A method includes isolating well-side equipment of a wellbore operation system from pump-side equipment of the wellbore operation system, wherein the pump-side equipment is connected to a well isolation unit via a single primary inlet to the well isolation unit and the well-side equipment is connected to the well isolation unit via a single primary outlet of the well isolation unit.