Bryan Doo, who left the Celtics in 2017 after a 14-year run as the team’s strength and fitness coach to focus on the growth of his private company, Optimal Fitness, believes a gradual ramp-up will be best for all concerned once the NBA sends out the call. “The thing we don’t think about is how great these guys are as athletes. They’ve been going since AAU, so it’s not necessarily a huge bad thing that they get a rest,” Doo said this week. “In the grand scheme of things I think these guys are such great athletes, they can adjust until it’s time to go back and play games. What I think will happen is that teams will go deeper in their benches, so guys don’t play as many minutes. That’s what I would do.”