American Robin with strange leg

So I shot this robin today and in camera I did not notice the left leg but when I was editing the take I notice what appears to be an injury that has healed over maybe even a broken leg, or is it somethig else all together. Thoughts?

Here is a tight look at the legs

Looks nasty. I've seen something like this on a roadrunner and assumed it was a healed break of some kind. didn't know about the mite problem.