By Tzvi Machlin The Brooklyn Nets are down 2-0 to the Boston Celtics in the playoffs and could probably use some reinforcements right about now. But will those reinforcements come from All-Star guard Ben Simmons? According to ESPN NBA insider Nick Friedell, the answer to that question is no. Simmons has been ruled out ahead of tomorrow’s Game 3 at the Barclays Center. The three-time All-Star has yet to make his debut for the Brooklyn Nets and has not played at all this season. But it’s believed that he’s on the verge of fully recovering from the back injury that has kept him off the court all …