No surprise, Rob Gronkowski doesn't travel to Buffalo

Rob Gronkowski didn't make the trip with the Patriots to Buffalo, per source.
— Albert Breer (@AlbertBreer) September 7, 2013

Gronk was highly unlikely to play Week 1, but is progressing nicely with some extensive work in practice.

The Patriots aren't likely to play him until he's completely healthy, which is expected to be sometime around Week 4 or 5. Any earlier, and the team might be pushing things.