Ligaments don't grow with the muscles. If I am the Bears, Houston is getting tested immediately and I am setting out to get some of my money back.
I jumped in the air for a header in HS and when I came down tweaked both of my calf muscles at the same time. Not the same as this, but it doesn't have to be steroids. It could just be a guy with tired limbs exerting himself in an unusual way and things just giving out. But ya, it may well be steroids.
I heard that it was a mild tear and that he may be able to return in limited capacity in 4-5 weeks. Of course his career could also be over.