Heat an oiled grill plate on medium. Toss the garlic clove onto the grill to heat through.
Grill sourdough until it is browned on both sides. Rub one side of each slice of sourdough with the garlic. Brush with 1 tsp of olive oil.
Toss together the turkey, grapes, half the basil, McCormick oregano, salt, pepper and balsamic. Scatter mix over each slice of bread.
Top with the remaining basil and a drizzle of the remaining olive oil.