Because there was no accurate documentation of it, no one knew what the precise color of the Yankee Stadium seats were in 1961. When faced with this dilemma, Production Designer Rusty Smith was told that Billy Crystal had an old bleacher seat from Yankee Stadium. Though the seat was completely painted blue, Smith found one small chip of green on the seat that proved to be the true Yankee Stadium green.
Contrary to the film's suggestion (and the widely held public impression), Commissioner Ford Frick never said that Roger Maris's home run mark would carry an asterisk because it was set in 162 games, while Babe Ruth's record was set in 154 games. As Frick said on 21 September, 10 days before Maris hit his 61st homer: "As for that star or asterisk business, I don't know how that cropped up or was attributed to me, because I never said it." Frick said the record books would contain two entries, with the same status. More importantly, he said he took this position because he was convinced baseball would revert back to a 154-game schedule within a few years, and allowing the new records to stand alone would make them unbreakable in a shorter schedule. Most people forget that only the American League, which had expanded to 10 teams, played 162 games in 1961. The National League, which still only had eight teams, played 154 games that year.
The fan who runs out and shakes Roger Maris's hand and slaps him on the back as he approaches home plate after his record-breaking 61st home run is an actual life-long Maris fan who was present at the original game. He was hired as a consultant and always wished he could have been that guy back in the summer of 1961 when he saw the game as a 13-year-old kid.
In the movie, Mrs. Ruth remarks how Babe Ruth loved his single season home run record in a sense that it was his favorite record. In fact, the record that Babe loved the most was his record of 29 2/3 consecutive scoreless World Series innings pitched, which, ironically, was also broken in 1961, by Whitey Ford.
The story Whitey Ford tells about Mickey Mantle tearing his knee because Joe DiMaggio made him back off a fly ball is true. According to Billy Crystal, Mickey had told him that story before and had even said "My knees were done right there and then."
In the scene before the Baltimore game where Roger Maris ties the record, the reporter is complaining about Roger not showing up for an interview and then begins to rip Roger for his attitude. According to Billy Crystal in the DVD Commentary, in real life the reason Roger stood up the reporter was because he was visiting a sick kid in the hospital. Crystal says he left that part out for two reasons: 1. Because the plot device of a ballplayer visiting a sick child was used too much in baseball movies (i.e.: The Pride of the Yankees (1942), among others) 2. It interrupted the overall tone of this section of the film which Crystal wanted to show the world against Roger Maris.
Most of the details of the games recreated for the film were based on Billy Crystal's first hand memories of having seen or watched the actual games. As a result, the film's crew members nicknamed him "Rain Man" for his uncanny ability to remember the games to the smallest detail.
Most images of the paths of the home run balls were CGI animation. Billy Crystal said he was having a hard time animating the proper arc and path of Maris's sixty first home run. During post production, Crystal attended Game 6 of the 2000 ALCS in which Yankees Outfielder David Justice hit a dramatic late inning Home Run at Yankee Stadium. Crystal credits seeing Justice's Home Run as helping give him the proper vision to depict Maris's historic Home Run.
The seats at Tiger Stadium were, at first individually covered with a green cloth material. However, once it was realized this was too time consuming (as well as expensive), it was decided to bring in a crew to spray paint the seats green (over spray on the cement can be seen in some movie footage). Upon completion of the movie, the seats were then steam cleaned to their original color. The cost to restore Tiger Stadium to its original appearance after the movie was made was $80,000.
According to Billy Crystal in the DVD Commentary, the scene of Mickey Mantle and Roger Maris doing the hot dog commercial was supposed to end with Roger's line "Hey, Mickey, shouldn't we be on the field?" But kept the cameras rolling and all of the "goofs" of Mickey and Roger laughing in the shooting were really the reactions of Thomas Jane and Barry Pepper which Billy decided to leave in the scene.
Yankee Stadium scenes were shot at a re-dressed Tiger Stadium in Detroit, Michigan in August of 2000. Infield seats at the stadium were painted green, and a partial third deck and 1961 Bronx skyline were added digitally in post-production.
According to Billy Crystal in the DVD Commentary, in the scene where Mickey Mantle throws a tantrum in the dugout and repeatedly punches the water fountain, Thomas Jane punched the fountain so hard that he broke a knuckle.
As a close friend of Mickey Mantle and his family, Billy Crystal was given permission by Mantle's family to honestly portray Mickey's drinking and carousing. Many of the moments in the movie of Mickey getting drunk really happened. This includes Mickey getting drunk and calling home at 2am from his hotel room as in the scene following the death threats to Roger Maris and his family.
In the film, Whitey Ford repeatedly calls Mickey Mantle "Slick". This is actually an in-joke that existed between Ford and Mantle. The story behind it is this: Back when Casey Stengel was the manager of the Yankees in the 1950's, he repeatedly reprimanded Ford, Mantle, and Billy Martin (who had already been traded away before the events in this film) for spending their nights drinking and coming to the ballpark the next day hung over. Stengel talked about the trio being "whiskey slick". So Ford and Mantle would jokingly call each other "slick" forever afterward.
Billy Crystal: he lends his voice several times in the film: 1: The director yelling "Cut!" when Roger Maris and Mickey Mantle try to film a commercial. 2: The Detroit Tigers' 3rd base coach yelling, "Hold Up! Hold Up!" 3: The TV announcer for Roger and Mickey's commercial. Billy also appears as a fan in the stands in the scene where Mickey gets a standing ovation as he starts batting practice on Opening Day. He can be seen in the upper deck crowd in the front, wearing a navy blue shirt.