Preheat the grill to medium heat.

In a large bowl, combine the Kielbasa sausage, redskin potatoes, red onion, zucchini, baby carrots, and yellow squash.

Place a large piece of heavy-duty aluminum foil on a flat surface and coat it with non-stick vegetable spray.

Transfer the sausage and vegetable mixture onto the center of the foil.

Dot the mixture with butter or drizzle with olive oil to your preference.

Season with salt, pepper, minced garlic, dried parsley, and Italian seasoning according to your taste.

Seal the edges of the foil tightly to create a packet, ensuring that it's well-sealed to prevent any juices from leaking.

Place the foil packet on a grill pan over medium heat.

Grill for about one hour, or until the vegetables are tender.

Make sure to flip the packet occasionally for even cooking.

Carefully open the foil packet, allowing the steam to escape.