Correct me if I'm wrong, but this is definitely not the end of a digit from a large carnivorous theropod. The only potentials from the Morrison formation where it was found, would be different species of ceratasaurs, allosaurs, and torvosaurus, right? and they, along with most carnivorous theropods have claws at the end of every digit, including the little foot&heel stubbies, don't they?
wouldnt this have to be from something without claws? Or at least no claw on this?