The daughter of a MLB pitcher who threw at Jackie Robinson's head in the movie "42" tells TMZ ... producers blatantly disregarded the truth and unfairly portrayed her dad as a racist.

It was one of the most important scenes in the flick ... big, bad Fritz Ostermueller (pitching for the Pittsburgh Pirates at the time) fired a baseball at Jackie's head ... and then shouted at him, "You don't belong here!!!"

Problem is ... Fritz never beaned Jackie in the head in real life -- according to multiple reports at the time of the incident, the ball struck Jackie's arm. 

Now, Fritz's daughter, Sherrill, is lashing out to TMZ -- "The producers of ‘42’ certainly owe my father an apology. If they were going to portray my father falsely, they should have used a fictional name."

Sherrill wants to make it clear -- her beef is NOT with Jackie ... "I have the deepest respect for Jackie Robinson and the courage he had to change baseball.”

However, Sherrill says producers have damaged her father's reputation beyond repair -- she tells us he was a "good man" who was never as angry or violent as he was portrayed in the movie.

We asked Sherrill if she believed her father was a racist -- to which she replied, "My dad, to my knowledge, was not a racist. I was not raised in that type of home."

We reached out to the people behind the movie -- so far, no word back.