"He would get his revenge on the base paths a little but he didn't shy away from contact when he was barreling into the catcher, those kinds of things," Helgeland said.
"You want to humanize him. The romance with the wife (played by Nicole Beharie) does that. The fact that he doesn't quite get along with (journalist and guide) Wendell Smith does that, which I think was the case in real life," he said. "You kind of need to go for this vibe: It's the actor and the director trying to have a feel for what feels real and right in the moment."
Baseball historian Howard Bryant, author and senior writer for ESPN.com and ESPN the Magazine, said he understands that some changes occur in making a film with historical origins, as was the widely publicized case with several 2012 Oscar contenders, including best picture "Argo." But he said Hollywood can't take liberties with stories like Robinson's.
"It would lose its credibility for me. I would lose respect for it if it were a Hollywood show," said Bryant, whose books include "Shut Out," about the role racism played in the Boston Red Sox' struggles. "We have a special talent in this country for scrubbing history, and I'm hoping that's not what happens to a story like Jackie Robinson's."
Bryant points out that Major League Baseball has been slow to diversify and still has a long way to go. In 2012, 8.8 percent of players were black, with only two black managers and two black general managers, according to the annual report by Richard Lapchick's Institute for Diversity and Ethics in Sports at the University of Central Florida.
"These stories are more important than ever as we throw around very loaded, misleading terms such as post-racial. I think it's even more important in something like Jackie Robinson's case because it wasn't that long ago," Bryant said. "Jackie Robinson died in '72 before the major leagues had integrated in the front office. Jackie Robinson died before there was a black major league manager" (Frank Robinson became the first black manager of an American League team — Cleveland Indians in 1975 — and the first in the National League — San Francisco Giants in 1981).