Measure and prepare the ingredients. Mince the garlic, onion, carrot, and celery into very small pieces. In a small pan set to medium, sauté the vegetables with a little olive oil until they are completely tender.
To make the meatball mixture, combine these ingredients in a large bowl: ground beef, sausage, egg, breadcrumbs, cooked vegetables, parmesan cheese, and Worcestershire sauce.
Put on some disposable gloves and mix the meat mixture by hand.
From here, roll the balls out into a consistent size and set on a sheet pan lined with a wire rack.
Preheat your pellet smoker to desired temperature.
When the Traeger has reached the desired temperature, place the wire rack directly on the grill grates and close the lid.
Cook the meatballs until they reach an internal temperature of 155˚F.
Remove the meatballs with the wire rack and serve immediately or transfer to a crockpot to keep warm.