NFL's Justin Herron Stops Alleged Sexual Assault At Park, Called 'Hero' By Cops

New England Patriots offensive lineman Justin Herron was heralded as a hero Wednesday ... after cops say he helped stop a sexual assault at a park in Arizona over the weekend.

The story is terrifying ... Herron says he was walking around Kiwanis Park at 11 AM on Saturday in Tempe -- when all of a sudden, he heard screams coming from the middle of a field.

Herron says as he approached the scene ... he saw a man on top of a woman -- and acted quickly.

"I just knew that in that moment I had to go and had to put a stop to it," 25-year-old Herron said.

The 6-foot-5, 305-pound lineman -- who was in Arizona training after wrapping up his rookie season -- says he screamed at the man to get off, before he physically pulled the guy away from the woman.

"Then I told him to sit down," said Herron, who cops say was also joined by another good Samaritan, Murry Rogers, in putting a stop to the alleged crime. "And, he just sat down and waited."

Cops say when they arrived on the scene, they identified the suspect as 30-year-old Kevin Caballero.

The victim, police say, was a 71-year-old who Caballero had pushed to the ground and attempted to sexually assault.

Cops awarded both Herron and Rogers Outstanding Service Awards for their actions ... and Rogers said the alleged victim called the two men "her angels."