Derek Jeter, the Yankees’ shortstop and captain, who is nearing the final act of a golden athletic career, is ready to talk about his life after baseball. He wants to be a book publisher. On Thursday, he is expected to announce that he will start his own publishing division, Jeter Publishing, a partnership with Simon & Schuster. Saying he had thought a lot about his future while recovering from injuries last season, he portrayed the move as a way to explore a project that combines his interests in business and content. “I think this sort of sets the blueprint for postcareer,” said Jeter, fresh off a plane from Tampa, Fla., and wearing a loose black blazer and jeans during an interview at his agent’s Midtown office on Wednesday afternoon. “This is a great way to start.” The publishing imprint will include nonfiction books for adults, like biographies and titles on business and lifestyle; children’s picture books; middle-grade fiction; and books for young children who are just learning to read. Jeter suggested the book enterprise might lead to other ways of presenting content, like films or television. Jeter Publishing, whose first books are expected to be released in 2014, might provide a partial answer to fans who have wondered what Jeter’s plans after baseball might entail. It’s a question that has been occupying him lately as he prepares for what might be his final season. He became the Yankees’ full-time shortstop in 1996, when he was 21, and will turn 40 in June. In the 2013 season, he was hampered by various leg injuries — all of them linked to a broken ankle he suffered in October 2012 — that sent him to the disabled list several times. Adding to the speculation was the departure of several of Jeter’s closest teammates — Mariano Rivera, Andy Pettitte and Jorge Posada — who retired in the last two years. But Jeter, known for his polite but unrevealing interactions with the press, has been circumspect about when he will make his own exit from the sport.