I wouldsay it is a rub for the fact that i have seen rubs that big before, and also it looks to be close to a creek or somthing and bucks love to follow those creeks. It is also the same heighth as a big bucks rack because of the guns heighth (i would say 40-42 in) it looks to be about right. In my opinion i would say it is a MONSTER rub.

NO rub, from what I can see, looks like the tree had a scar there and the bark has peeled off of it a little and the limbs there scraped it enough to roughen up the exposed bark

Thats a hard picture to tell. I don't think it would be a rub though. Like the others say, it's to close to the ground.