One medium zucchini, cut into 1-inch pieces, can be used in place of the mushrooms in this recipe.
If a grill basket isn't available, make sure the vegetable pieces are large enough so that they don't fall through the grill. Also, cut the vegetables the same size so all the ingredients cook in the same amount of time.
Cut the vegetables up to one day in advance; cover and refrigerate them. Toss the vegetables with the oil mixture just before cooking.