Precooking white alabama bbq sauce chicken in oven

I've done boneless chicken thighs this way, but not tenderloins. For the thighs, I usually remove from the marinade and dry off. Then bake in a 350F oven for about 30 minutes. Remove them from the oven, cool and chill until you are ready to cook them on the grill. I take them out of the fridge about half an hour before grilling, so they are not completely cold. Apply the first coat of white BBQ sauce, put on grill and cook until done. It would be tricky to do the tenderloins, and I've never done that so the best I can say is try it at the same temperature and just monitor the doneness level so you can stop it before they cook through in the oven. I would guesstimate about 15 minutes, but it would depend on the thickness. Then I'd chill and proceed the same way as you do with the thighs. I don't recommend microwaving or boiling, because one gives you rubber chicken, and the other washes away a lot of flavor.