It has been more than six weeks since D’Angelo Russell underwent arthroscopic knee surgery, and since Nets general manager Sean Marks previously indicated his return might take eight weeks, he might soon be ready to to practice. But coach Kenny Atkinson declined to provide specifics about Russell’s status before the Nets ended a five-game road trip with a tough 108-105 loss to the Celtics Sunday night. “He’s progressing along with our schedule,” Atkinson said. “I’d just say he’s working his tail off. I was watching him in the gym yesterday. It’s an arduous process. He’s putting in a ton of time, he’s putting in full days. It’s been amazing to see his work ethic. He’s been great.” Russell was the starting point guard when he was injured, but Spencer Dinwiddie has been terrific as starting point guard since then and Caris LeVert is playing his best basketball with the second unit.