The manager of the New York Yankees is played by Augie Garrido, who befriended Kevin Costner while he was the head coach at Cal State Fullerton. Garrido has been the head coach at the University of Texas since 1997, and the two remain good friends.
The shots of Billy Chapel's parents at the beginning of the movie are Kevin Costner's actual parents.
According to Kevin Costner, Yankees owner George Steinbrenner was becoming agitated that the Yankees would be seen losing in a movie filmed on location at Yankee Stadium. Costner said he was able to calm Steinbrenner down by explaining that Billy Chapel, and not necessarily the game itself, was the movie's major focus. Costner also explained that the game would mean nothing to the Yankees, and that it wasn't played as a "Winner Take All" scenario. Costner convinced Steinbrenner that in the movie's universe, the Yankees would clinch the AL East division the next day, keeping alive their World Series chances. Costner said that he later received a Yankees 1999 World Series ring as a thank-you gift from Steinbrenner.
It was reported that Kevin Costner was angry with Universal Pictures because they cut his full-frontal shower scene. Costner told Newsweek that the studio lacked "real courage" by insisting that the film have a more kid-friendly rating. But a studio executive told New York magazine that a test audience in Arizona gave a thumbs-down to Costner's manhood. "The audience giggled at Kevin's penis... Then, in focus groups, they said, 'Do we really need to see Kevin Costner's penis?'"
Dave Eiland (the only major league player ever to give up a homerun to the first hitter he faced, and hit a homerun in his first plate appearance), who played a relief pitcher in the bullpen and celebration scene, was also Kevin Costner's pitching double in some long shots. He later went on to serve as pitching coach for the Kansas City Royals and New York Mets.