In response to Uffda's medical info, I'm not a P.T. but my hunch is if the Packers could diagnose an ACL tear with their tests rather than an MRI, it's pretty severe and the stability of the knee is pretty bad.
As far as preseason, every fan holds their breath this time of year, and I get AR's frustration, but you have to practice at some point. We're trying to avoid a 1-2 start, I can't confirm but sense we've babied CM3, Sitton, Bahktiari, and others (which I'm fine with), but you can't live in a complete bubble from February to opening day. Like you said Luigis, this was non-contact.