If it is a hole and not a drain and you want to make it look good again without a patch, there is a product at most auto part stores called thermosteel you can patch over pretty good size holes, I have used it several times on my old smoker. It is made for repairing holes in car manifolds/exhaust and is extremely heat resistant (up to 2400 degrees). It comes with a metal mesh you can place over the hole and cover with this mixture up to 1/4" thick and it can be shaped with a grinder to make it look like a hole was never there. It has worked excellent for me in the past.
Making smiles one rib at a time.......