Lots of celebrities throw out a first pitch. But former Boston Symphony Orchestra music director Seiji Ozawa never went to Fenway to be seen. His fandom? “It’s real,’’ says BSO managing director Mark Volpe, on the eve of Ozawa’s visit to Boston this week. The conductor, who left the BSO in 2002, is coming for personal, not professional reasons, and Volpe has a hunch where you might find the maestro over the weekend – that is, if the Sox can’t wrap up the pennant in Detroit Thursday night. “All those years, [Ozawa] suffered,’’ said Volpe of the Sox’s decades of futility. “All of a sudden he leaves, in 2002, and we win something.’’ When Ozawa began conducting the Vienna State Opera in 2002, he would go to the American Embassy in the morning to catch the Sox. Eventually, the BSO hooked him up with an Internet streaming service. Volpe hopes that if Ozawa has time, he’ll stop into Symphony Hall and pose for a few photos with new music director Andris Nelsons. Of course, he might be better off hauling Nelsons back to Fenway. When Ozawa left the BSO, one of his parting gifts came from the Red Sox: a lifetime pass.