In a large skillet cook the bacon over moderately low heat, stirring, until it is crisp, transfer it with a slotted spoon to paper towels to drain, and pour off all but about 1/4 cup of the fat. In the fat remaining in the skillet cook the garlic, the onion, and the celery with the thyme and the sage over moderately low heat, stirring, until the vegetables are softened and transfer the mixture to the bowl. Add the parsley, the melted butter, the oysters, the bacon, and salt and pepper to taste, toss the stuffing well, and let if cool completely.
The stuffing may be made 1 day in advance and kept covered and chilled. (To prevent bacterial growth do not stuff the turkey cavities in advance.)