I'm not too concerned about Hernandez being out. This reminds me of Spikes' and Chung's (mostly Chung's) situation last season. They both got injured, the team tried to bring Chung back earlier, had a setback, and was then held out until the end of the season. With Shiancoe, we can afford to have Hernandez sit out until December / January. We can win without him, but come playoff time, it'd be great to have him healthy.
As for Chung being out, I'm expecting a McCourty-Gregory Safety tandem.