Preheat oven to 400F. Slice potatoes, peppers and onions as mentioned above. Place onto the sheet pan and drizzle with oil. Season with oregano, salt and pepper and toss together to evenly coat everything.
Spread out potatoes and vegetables evenly on sheet pan and place the sausages on top. Bake in the oven for 30 minutes.
After 30 minutes, flip potatoes, vegetables and sausages. Continue to bake for an additional 20 minutes or until the sausage is cooked through and the potatoes are fork tender. If the sausage and potatoes don't have much colour on them, broil on high for a couple of minutes, keeping a close eye on them to ensure they don't burn.