For La Piedra, it was the feeling of la familia that made him want to eschew the flexibility of his looming free agency and commit to the Mariners for the next five years and perhaps beyond. Two days after announcing the signing of right-hander Luis Castillo to a five-year, $108 million contract, the Mariners held the formal news conference at T-Mobile Park to discuss the latest long-term commitment to a player. “I’m just very happy that I’m finally able to join this family long term,” Castillo said through interpreter Freddy Llanos. “I’ve got to give everything, all my heart. We’re prepared t…