NEW YORK — Nets star Ben Simmons will undergo back surgery on Thursday, adding yet another chapter to the saga that’s been his delayed debut in Brooklyn. The Nets announced Wednesday that Simmons will have a microdiscectomy to alleviate the pain associated with the herniated disc he developed in his lower back after his arrival in Brooklyn — via the Feb. 10 James Harden trade with the Philadelphia 76ers. “After consultation with multiple back specialists, it has been determined that the best course of action for Ben’s long-term health is for him to undergo back surgery,” the Nets announced in …