The Nets’ rebuilding was always going to be near-impossible because they lack their own draft picks, presumably franchise-changing lottery ones to get a transformational player. In the Nets’ 133-114 preseason-ending loss to the Sixers on Wednesday, Joel Embiid reminded them just how pivotal a young player of his caliber can be. The oft-injured Embiid had 22 points, seven rebounds, hit 14-of-18 from the free-throw line and dominated on both ends of the court. And that was all in just 14:45 of his preseason debut — his first game since Jan. 27. Transformational? Not even a question. Nets coach Kenny Atkinson said the 23-year-old center isn’t one of the NBA’s best young players; he’s already one of the league’s top talents of any age. “Without a doubt. He’s a top player in this league already. There’s no denying it,” Atkinson said. “He’s going to be a handful for everybody in this league, and he’s unique because he can go in the post and go out and he’s fast. I think the big real compliment is how he competes defensively. He blocks shots, he’s really an impressive young player.” Too agile and athletic for Timofey Mozgov and too big and strong for any other Net, Embiid had 20 points and seven boards in just 11:28 in the first half, putting the Sixers on his back and putting the Nets in a 76-51 hole.