I have a food safety question regarding a steak with brown spots on it.?

Was the steak covered in the fridge? Could the brown spots be due to being exposed to air? Did you smell it before you froze it? Was is sticky/slimy? Do you want to risk getting sick? I would thaw it out, give it a good inspection (sniff, poke, prod and the what not) and if it still seems alright, I would cook it. Maybe I would feed it to someone else, but a Ribeye is a Ribeye, and Ribeyes are expensive. 4 days is pushing it to be left in the fridge though... Good luck.