In a bowl, combine butter with thyme, minced garlic, rosemary, sage, pepper, and salt.
Separate the skin from the defrosted turkey breast and insert butter mixture into the pocket, covering the entire breast and outside of the bird generously.
Rub the exterior of the turkey with kosher salt and fresh black pepper.
Preheat pellet grill to 225°F
Place your turkey on the pellet grill and close the lid. Place an aluminum foil drip pan underneath the turkey and fill with 2-3 cups of water to help keep the environment moist.
Smoke the turkey for 6-7 hours. The turkey is ready to come off of the pellet grill when the centermost point of the breast reads an internal temperature of 165°F on your probe thermometer.
Remove turkey from grill grates and let it rest on a dish or serving platter for about 20 minutes.