Bring a large pot of water to a boil and cook macaroni according to package directions.
Meanwhile, in a large skillet, brown Italian sausage. Strain and set aside. Reserve 1 tablespoon of pan drippings if possible.
In the same pan that you cooked the sausage in, add reserved pan drippings and 1 tablespoon of olive oil. If there were not enough pan drippings add another tablespoon of olive oil. Stir in garlic and let cook for 30 seconds. Stir in mustard greens. allow to cook just until wilted, about 2 minutes. Return sausage to the pan. Stir to combine.
By this time your pasta should be just about ready. Strain it and mix it with the sausage and greens. Pour the tomatoes over the top. Season to taste with salt and pepper. Allow to cook for 5 - 7 more minutes or until the tomatoes are warmed through. Serve.
Mustard greens really work the best in this recipe but kale would be a fabulous substitute. This reheats fabulously so it's great for lunches. Nutrition facts for estimation purposes only.