Slice the sausage into 1/2-inch pieces. Heat 1/2 tablespoon of oil in a skillet over medium heat. Cook sausage until browned, about 3 minutes per side. Transfer to a plate.

Reduce heat to medium-low. Add remaining oil and cook chopped onion until softened. Add minced garlic, chopped cabbage, salt, and pepper. Toss to combine, cover, and cook for about 12 minutes, stirring occasionally, until cabbage wilts.

Stir in red wine vinegar, return sausage to the pan, stir well, and cook for 3 more minutes until heated through and cabbage is tender. Taste and adjust salt if needed. Serve hot.