Place a large pot of salted water over high heat and bring to a boil. Cook the orzo according to the DeLallo package instructions and drain, saving 1 cup of the pasta water for later use. (If you plan to use this stuffing in a bird, undercook the pasta a little bit.)
Meanwhile, place a large skillet over medium-high heat. Add the bacon to the skillet and brown until just cooked through. Then add the celery, onions and carrots to the skillet and saute for 2-3 minutes. Add the apples, stir and saute another 2-3 minutes until soft, but firm.
Now mix in the cooked orzo and sage. Toss well and add 1/2 cup of the reserved pasta water to help the flavors mingle. Toss and cook another 1-2 minutes, using more pasta water if needed. Taste, then salt and pepper as needed. Serve warm.