The NYPD has modified its official patrol-guide order on the use of deadly physical force, by adding four words — a change apparently intended to protect the department from future potential lawsuits, The Post has learned.

In the section referencing the use of firearms, the NYPD inserted the words “in their professional judgment.”

The passage now reads: “Police officers shall not discharge their weapons when, in their professional judgment, doing so will unnecessarily endanger innocent persons.”

The change was made after a negligence suit was filed by an innocent bystander wounded in crossfire.