The bat that bat boy Bobby Savoy gives Roy is called the "Savoy Special". The Savoy Special was a brand of beer in the 1930s, and was made by the United States Brewing Company. This bat is now in the collection at the National Baseball Hall of Fame and Museum in Cooperstown, New York, displayed along with Roy Hobb's jacket in an exhibit titled "Baseball and the Movies".
While Darren McGavin had a major supporting role as the bookmaker Gus Sands, he received no credit. In the recent retrospective documentary on the Special Edition DVD of this movie, Robert Prosky (the Judge) claimed McGavin was cast late in the picture, and would have received a lesser billing than the other stars. Thus McGavin chose to go uncredited. Prosky noted where McGavin wound up "drawing more attention to himself" as a result.
The quote by Roy Hobbs about what it takes to be a big leaguer, "You have to have a lot of little boy in you", was actually a quote by Brooklyn Dodgers catcher Roy Campanella.
Hobbs breaking the scoreboard clock with a home run was inspired by Bama Rowell of the Boston Braves doubling off the Ebbets Field scoreboard clock on May 30, 1946, showering Dixie Walker with glass. Though he'd been promised a free watch by Bulova for hitting the company's scoreboard sign, Rowell had to wait until 1987 to receive it.
Glenn Close's initial appearance at the ballpark was carefully planned to give her the appearance of a guardian angel. They waited until a clear day, when the setting sun would be just at the right spot in the background to shine through her translucent hat, making it appear as a halo around her head.
Barry Levinson: [Ralph Tabakin] (Al's customer) has appeared in every Levinson picture from Diner (1982) to Liberty Heights (1999). Levinson, a Baltimore native, is also an Executive Producer, and sometimes director, of Homicide (1993), where Tabakin had a recurring role.