Mix the beef, rice, onion, egg, salt, garlic powder and pepper just until combined and shape into 18 meatballs.
Heat the oil in a deep skillet over medium-high heat and brown the meatballs in 2 batches for 5 minutes per batch.
Stir the crushed tomatoes, broth and Worcestershire together in the skillet and return all the meatballs.
Cover and simmer over low heat for 35 minutes, turning the meatballs once, until the rice is tender and the centers reach 160°F.
Uncover and simmer for 5 minutes if the sauce is thinner than a spoonable gravy.