When the bat boy tells Crash Davis "Get a hit, Crash", Kevin Costner ad-libbed the response of "Shut up." Since the kid actor playing the bat boy obviously didn't know this response was coming, he started crying.
The "rainout" scene was based on actual event. In the late 1960s, Ron Shelton played minor-league ball in the Texas League. Shelton's team was in Amarillo, Texas for a season-ending series. The night before the final game, Shelton, some teammates and some Amarillo players were out partying and decided to go to the stadium and turn on the sprinkler system, thereby flooding the field and ensuring a "rainout". However, the Amarillo team owner rented a helicopter, dried the field, and the game was played.
Kurt Russell helped Ron Shelton develop the script and was originally penciled in to play Crash, the part that went to Kevin Costner. After the film was made, Russell was so impressed, he actually wrote fan letters to Costner and Shelton.
There really was a ballplayer named "Crash" Davis. Ron Shelton found his name in a baseball listing as a minor leaguer and American Legion player. Realizing that he would have to have the permission of the real Davis to use his name (and thus avoid a lawsuit). When Shelton approached Davis, he was asked "Do I (Meaning Kevin Costner) get the girl in the end?" Shelton told him he does and Davis signed off his permission.
According to director Ron Shelton in the DVD Commentary, he came up with the name Ebbie Calvin "Nuke" LaLoosh (Tim Robbins) after being served in a restaurant by a waiter named Ebbie Calvin "Nook" LaRoosh. Shelton thought it was a stand out name and changed the spelling of the nickname and last name.
Although Kevin Costner plays the 'older' more experienced ball player, in real life he's only three years older than Tim Robbins (33 and 30 respectively during filming), and Susan Sarandon was actually in her early forties (42). Additionally, Costner is about three and a half inches shorter than the very tall Robbins (almost 6'5").
The costume designer did a little research and learned that the last baseball jersey number director Ron Shelton ever wore as a minor league player was number 8. So she gave Crash Davis (Kevin Costner) that number.
During a conversation between Crash and Nuke on the team bus, a newspaper's sports page is shown briefly with a headline reading "Hard-hittin' Whiten". At the time the movie was filmed in 1987, Mark Whiten was a top prospect for the Toronto Blue Jays in the South Atlantic League and made that league's All-Star Game. Whiten said he missed his brief moment of fame when he first saw the movie in the theatre, but caught it when he rented it later. Whiten went on to have a fairly ordinary 11-year career in the majors highlighted by one 1993 game in which he tied two major league records with four homers and 12 RBI.
The bar scene takes place in Mitch's Tavern on Hillsborough Street in Raleigh, North Carolina, across the street from NC State University. Today, in Mitch's there are a few mementos from the movie: framed film still of Crash Davis and Annie Savoy (autographed by Susan Sarandon and Kevin Costner) and the glass door which Nuke Laloosh breaks is framed. The furniture, fixtures, and layout of the tavern largely remain the same as they were in 1988.
In the scene where the Bulls have returned from the long road trip, Annie is seen at the game wearing a black veil and appearing as if she had just come from a funeral. This is because the previous scene, where Annie attends Max Patkin's funeral, was deleted in post-production. Ron Shelton had written a scene where Max was killed in a car crash during the season.
Ron Shelton reportedly based the character of Nuke LaLoosh on a minor league teammate from his playing days named Steve Dalkowski. Dalkowski is something of a legend among baseball fans and is widely regarded as the fastest throwing pitcher ever. Unlike the character in the film, Dalkowski never made the major leagues.
The movie was filmed on location in North Carolina in October and November, 1987, which is why the grass had to be touched up with green paint. It is also why the breath of the actors can be seen in many of the night scenes.
In one scene, 'Nuke' LaLoosh (Tim Robbins) gives up a home run that strikes the bull, supposedly rewarding the opposing hitter with a free steak. In reality, at the old Durham Athletic Park, the bull was in foul territory.
In their confrontation outside the bar, Crash tells Nuke, "I hear you couldn't hit water if you fell out of a fucking boat." Dodgers manager Tommy Lasorda said this in 1984, in reference to weak-hitting San Diego Padres infielder Kurt Bevacqua.
Originally, after Annie and Crash have their argument in Crash's apartment, there was a scene in which Annie and Crash go to a bar and have a heart-to-heart talk. In the talk, Crash asks Annie why she loves baseball so much. She explains that several years before, her estranged father passed away and that the funeral took place in Florida. She was so distraught after the funeral that she wandered off and ended up at the New York Yankees spring training facility where she met legendary Yankees catcher, Thurman Munson (thus explaining her shrine to Munson seen in the film). From then on, she developed a deep-rooted love of the game. According to Ron Shelton in the DVD commentary, he cut that scene out when it was received poorly during a test screening. After the scene was removed, a second test screening was done and the movie received a high score.
Early in the film Kevin Costner's character states that he thinks Lee Harvey Oswald acted alone. A few years later he would star in JFK (1991), whose protagonist believes Oswald did not act alone and was possibly a fall guy for the Kennedy assassination.
The "big club" is referenced several times during the movie, though it is never made completely clear what major league team the Bulls are affiliated with. At the time of the filming, the Durham Bulls were a Carolina League Single A affiliate of the Atlanta Braves. As of 2013, the Durham Bulls are the Triple A affiliate of the Tampa Bay Rays.
In one memorable scene, the Tim Robbins character sings a song incorrectly, using the word "wooly". Four years after the movie's release, the Durham Bulls named a new mascot. Since the Depression, the mascot had been a bull, but in 1992, they created the character "Wool E. Bull", which sounds like "wooly" but has "E" for "education".
Near the end of the movie, Annie quotes some poetry in a voiceover and then says "That was Thomas Gray. Or William Cullen Bryant, I forget which." It was indeed Thomas Gray and it was taken from "Elegy Written in a Country Churchyard".
When Nuke says, "Annie, I know you're in there, I can hear that crazy Mexican music," the song on the phonograph is 'Non, Je Ne Regrette Rien'. It is a famous recording by Edith Piaf, who is singing in French.
Nick Nolte, one of the biggest male stars at the time, turned down the lead because he had just finished several movies back-to-back, and, most importantly, because he isn't a fan of baseball. Nolte famously played a footballer in North Dallas Forty (1979), a movie he co-wrote.