I did that once with a turkey, quite by accident. Totally ruined the presentation of the bird - it fell apart when I tried to remove it from the roaster and of course it didn't have that lovely browned skin over the breast. The meat was excellent though.
One trick to moisten breast meat is to carefully separate and slightly lift the skin (without tearing or breaking it) from the top of the turkey just enough to slip your hand under it, and rub softened butter between the skin and turkey breast. You can also add poultry seasoning or garlic powder to the butter. The melted butter will slowly baste the breast meat as the turkey is roasted. If you have an unbrined turkey you can use bacon grease instead. Note that every frozen turkey in the grocery store has been brined, and if you use bacon grease on a brined bird it gets oversalted.