I'd say it's potential, but not full bumble. It looks irritated, injured, could be from the hot pavement, or something else irritating it. I can't tell if the dark spot is scab or just dirt/droppings stuck in there. I personally would treat it like early bumblefoot and treat it topically. A soak in epsom salts will help with swelling and inflammation, and clean off any dried dirt/droppings. Apply a plain triple antibiotic ointment and wrap the foot/feet to keep them clean and dry. I would reapply daily or every other day until it's looking better. If it looks like more after soaking, post some pictures of it then.
