Sometimes Campbell Scott fans have it tough. Like any great actor, he seeks out different material. Like a renegade, he avoids the mainstream. But it’s starting to feel like for every Roger Dodger, a movie he singlehandedly turned into a mini-classic, there’s a misfire like Saint Ralph. Here he plays Father Hibbert, a buttoned-up man of the cloth who coaches Ralph (newcomer Butcher), a big-eared Catholic ninth grader convinced that if he wins the 1954 Boston Marathon, it’ll be the heavenly miracle that’ll jolt his mother from a coma. At first, Ralph and the movie have moxie — the kid even gets busted for pleasuring himself in the public pool. Then Ralph starts asking us to take this cornball mission seriously. By the end, the beanpole is logging 4:25 miles and impossibly chugging slo-mo through rainy Boston on race day, helping Father Hibbert get his faith back. It’s as if Max Fischer from Rushmore turned, mid-movie, into Billy Elliot.