On 27 October 2004, Game 4 of the 2004 World Series between the St. Louis Cardinals and Boston Red Sox, the finale of this film was shot. After the last play of the game in the bottom of the ninth during the Red Sox celebration, stars Drew Barrymore and Jimmy Fallon were filmed also celebrating together on the field. A brief shot of the filming could be seen live on the Fox broadcast of the World Series. Rewrites by Peter Farrelly and Bobby Farrelly had to be done immediately following the World Series game 7 clincher of the ALCS against the New York Yankees to include the historic 2004 Boston Red Sox post-season.
Footage from a game in Toronto, Canada between the Yankees and the Blue Jays on 1 October 2004 was shot for the movie. Drew Barrymore and Jimmy Fallon were present at the game and she threw out the first pitch.
Ben has a gigantic replica of Fenway Park's left field wall (a.k.a. "The Green Monster") on the wall of his apartment. In real life and in his apartment, the wall includes a hand-operated scoreboard. The particular game immortalized on Ben's mural is that of Game 3 of the 1999 American League Championship Series, won by the Red Sox over the N.Y. Yankees, 13-1. Before Boston's conquest of New York in 2004 (depicted at the end of the film), the '99 game was one of the most memorable Boston wins in recent memory.
Another game filmed for the movie was the September 16, 2004 game against the Tampa Bay Devil Rays, which Boston won 11-4. The shooting consisted of Drew Barrymore running across the field to where Jimmy Fallon was sitting, near the Red Sox dugout. This was filmed after the game, with about half the crowd staying after to be extras.
The Opening Day sequence was filmed on 4 September 2004 with Stephen King throwing out the first pitch; the Red Sox lost that game, ending a ten-game winning streak and King was blamed for it in the Boston Globe.
Exactly 17 members from the Boston Men's Baseball League were selected to appear as player extras in full uniform in the film. Filming took place at Fenway Park from September 16-23, 2004 from 5pm to 5am nightly. Included in the cast from the BMBL were: - Boston Athletics: John Howe - Boston Cardinals: Dan Jalbert - Boston Marlins: Andy Katz - Boston Rockies: Dave Mitrou - Boston White Sox: Ryan Gray & Jason Hoye - Cambridge Cubs: Billy Burton & Jamie Waters - Medford Mets: John Collins - North Andover: Paul Laurin - Somerville Senators: Michael Sawyer & Russ Ward - T's Pub Dodgers: Scott Gilefsky & Andy Hickey - Wayland White Sox: Jerry Dawson, Dana Johnson & Steve Wolf
The film mentions the long standing story that former Red Sox owner and Broadway producer Harry Frazee traded Babe Ruth in order to finance the musical "No, No, Nanette". While it may have some truth to it, the deal was much more indirect and complex. Babe Ruth was traded to the Yankees for $100,000. "No, No, Nanette" was originally a non-musical stage play named "My Lady Friends". Without the Babe Ruth trade, "No, No, Nanette" would not have been on Broadway.
During the flashback to the first game that Ben's uncle took him to we see three actual former 1980 Red Sox players playing themselves. Two are very recognizable star players Dennis Eckersley and Jim Rice. The other is Keith MacWhorter who only pitched one season in the majors. His career record was 0 wins and 3 losses in his 24 game career.