With three days left until the NBA trade deadline, the Pistons have made the most significant move of the trade season, adding Blake Griffin to the frontcourt with Andre Drummond. The move took away two starting wing players, so the prevailing thought is the Pistons could be making another move before Thursday to shore up their perimeter. Having given up Avery Bradley and Tobias Harris, there aren’t many other assets that general manager Jeff Bower has at his disposal with which to barter. That makes forming a Big Three a bit more difficult, but Pistons coach Stan Van Gundy said the triumvirate already exists. “To me, the third piece is Reggie (Jackson). That’s pretty good. That’s a pretty good three,” Van Gundy said Monday. “We’ve got it in place; we just don’t have it on the court right now.” Jackson is progressing from his ankle injury and took some set shots after practice Monday, but still isn’t close to returning before the All-Star break, from Feb. 15-21.