Who knows, the Packers aren't going to tell us anything, it's too early to care too much, and we'll find out later. It's a concern because he's a great player that was missed last year. But there really isn't much to take from this story. It "could" be a lot of things. It could be because he's been training too hard in his drive to get back and over did it. It could be he's had an underlying issue in that knee that is just now flaring up, maybe he did just tweak it, it swelled and it will be better in 3 days. Maybe his biomechanics have been subtly changed because of the other knee and that is causing this issue? What does it mean? Does it matter? Last year he was looking and feeling great, landed wrong on a high pass and that was all she wrote. In the past he's had bursitis, pulled hammy, diagnosed with nerve damage in knee, and a strained PCL in the knee and sometimes missed games, sometimes didn't.
Things hurt, it's football, they train pretty much year round so having something hurt now isn't uncommon. keeping a star player coming off of surgery, in a season where you have an extra game and week of TC, who has been training hard all offseason, off the practice field for a week or 2 isn't really a big deal either. I guess it gives us something to talk about, but someone who is completely healthy will go down for the year and someone that is always injured will play in every game. It's football.