Filmmakers Ricki Stern and Annie Sundberg weren’t serious fans when they started working on their baseball-themed documentary “Knuckleball,” but their uncanny choice of subject material not only suggests they may have a future in player development but has also proved to be a game-changer for their film.The movie chronicles the experiences of two pitchers, the New York Mets’ R.A. Dickey and the Boston Red Sox’s Tim Wakefield, during the 2011 season as they battle to succeed at the Major League level throwing baseball’s rarest pitch, the knuckleball. While the story is compelling, the project’s prospects took an upward turn when Dickey’s career trajectory unexpectedly skyrocketed this year, with the journeyman pitcher suddenly becoming one of the top performers in the National League. (Wakefield retired before the start of the 2012 season after 17 years in the majors.) “At the end of the 2011 season, R.A. Dickey was no one’s idea of a star,” ESPN Insider baseball writer Paul Swydan says. “But he has become a marquee attraction — the kind of player that both die-hard fans and casual fans are excited to see, whether it be at home in Flushing, N.Y., or out on the road. That he has done this at age 37, which is very old for a professional baseball player, makes his story that much more remarkable.” FilmBuff, a distribution company that specializes in Video on Demand, secured distribution rights to the doc in June, with Dickey riding a nine-game personal winning streak that would peak at 11. Still, at the time, he had yet to establish himself as a full-fledged media darling. But as the season has worn on, Dickey has hit his stride, including an engaging appearance on “The Late Show With David Letterman” in July, and the sales success of his memoir “Wherever I Wind Up: My Quest for Truth, Authenticity and the Perfect Knuckleball,” which hit the New York Times bestseller list. Suddenly, the film’s game plan was transformed. “I could have spent millions of dollars and not created the phenomenon that R.A. Dickey has become,” says FilmBuff head of marketing Julie La’Bassiere. “There’s no question that had he not had the type of season he’s having, we probably wouldn’t have been able to do everything we’re doing.” Considering Dickey’s newfound profile, FilmBuff is giving the movie a limited theatrical release with weeklong runs in Boston (beginning Sept. 18) at Coolidge Corner Theater, and in New York, starting two days later, at the IFC Center. Also, in part to capitalize on the currency of Dickey’s story, Filmbuff added the pic to its VOD schedule as quickly as it could. With the significant lead time required to get a project in the pipeline for cable delivery, September was the earliest debut dateit could manage; the docu will be released on VOD in conjunction with its theatrical bow Sept. 18, with DVD sales set to begin in December. While the long lead time has left the film unable to capitalize on the team’s early-season success (the Mets have fallen out of playoff contention), Dickey remains a candidate for the Cy Young Award, which goes to each league’s best pitcher. Even with the truncated schedule, Dickey’s success has helped ease the marketing process, particularly in New York. With the city’s long timelines for advertising in public spaces, La’Bassiere worried she might have difficulty securing bus shelter advertising locations for “Knuckleball.” But when she explained to municipal representatives that the film starred Dickey, they “bent over backwards” to line up space for the film. As a result, there will be approximately 20 ads on bus shelters to coincide with the doc’s opening. Special events supported by city officials in Boston, where former Red Sox pitcher Wakefield remains an icon, and in New York are also planned. And the Dickey bump should continue. Filmmakers are now in negotiations for a TV rights deal for the documentary, and are aiming for an airing next spring, when a new season begins and fans show renewed optimism. As to how the project will do in its upcoming VOD and theatrical runs, its distinctiveness certainly won’t hurt. “This is a very unique situation,” says Jeff Freedman, who runs FSPR, a Los Angeles-based firm that specializes in marketing sports-related film, television and book projects. “It is uncommon for a sports documentary to be about a player in his prime, or one who is still playing. … Having R.A. Dickey succeed beyond expectations coincident with the release of ‘Knuckleball’ is a most fortunate and rare synchronicity.” In other words, you might say the knuckleballer has thrown marketers a curve.