Question: Can I Brine my Turkey AND use a Rub or Injection Marinade?
Answer: You are planning on a brined turkey this year. Can you also apply a Turkey Rub and/or use a Turkey Injection to add extra flavor? The answer is yes, but. While properly brining a turkey won't make it too salty, it does add salt to the meat. If you then add a salty rub or injection marinade you can end up with a turkey too salty to eat. For this reason, if you are brining your bird, make sure you rinse it thoroughly after it comes out of the brine, and do not use a rub or injection marinade with salt. Now if you take a look at Turkey Rub Recipes or Turkey Injection Recipes you will find that most of them contain salt. Since you have already salted your turkey, simply omit the salt from these recipes and you will be ready to go.
I do suggest that if you are doing more than one of these (brining, rubbing, injecting) that you use similar ingredients so that you don't confuse the flavors.