Sitton is just resting his back, it doesn't look like a re-injury of it: http://www.jsonline.com/sports/packers/sitton-trying-to-get-back-ready-b99635759z1-362742271.html
From the same article, this is what McCarthy had to say about Montgomery: "He's progressing, hopefully he can get through a week of practice." That doesn't look particularly promising to me and although it's been 2 months, I'd still prefer they error on the side of caution. I'm not sure about Shields - will they go as late as Saturday to make a decision on him?
So are glaciers.
That's good to know about Sitton; I thought it was a new injury.
With a concussion, I'd always wait as long as possible.