How long is refridgerated ground beef good for?

Today is Sunday. On Friday night, I took my frozen hamburger and placed it in the refrigerator, and two days later, I am just now ready to use it. I completely forgot about it being in there. It was COMPLETELY frozen when I first placed it in the fridge so it probably took a few hours for it to completely thaw out... Is it still good? Im making spaghetti and Im considering almost burning the hamburger just to be safe lol. But, it smelled completely fine, no bad odors.. it wasnt really grayish or anything.. It was really rather pink. SO it looked good, smelled okay, is it still alright?