I agree there's a bit of a wrinkle here, but the non-trade or backup options are pretty marginal. So long as you still think Brady wants to play beyond 2017, you really have to deal Jimmy this offseason.I don't know that it much matters from the Pats' perspective.
If they are open to trading JG at all, they'll have a price point, and, sure, an active bidding market would help them once that threshhold is reached.
But the main thing here is risk aversion. If you're without an above-average QB for 10 years, you're MF'ed for 10 years -- at least by comparison to the last 16 years.
And it's tough. How long can Brady play at this level? Is JG a worthy successor? Brissett?
Five years ago, it's pretty easy. What can I get for JG? How does that compare to a 3rd round compensatory pick next spring? What's the value of having JG as insurance for a year?
Now it's more complicated.
If you're worried about Brissett as a backup for a few games max, you can bring in a veteran. The only scenario where keeping Jimmy is likely to outweigh his projected trade value is if Brady either suffers a career ending injury in 2017, or makes a surprise decision to retire (prompting you to keep JG and extend him).
I don't think the risk of TB hanging them up early or getting Theismann'd is that high. It can happen, but my guess is the Pats think there's a 90% chance or better that TB is their starter in 2018. If that number were like, I dunno, 50%, then it becomes a real dilemma. And there is still real risk in letting JG go no matter what, I don't mean to minimize that. But I think the number one issue is where you think Tom will be in 2018, and so long as the answer is "here," you've gotta get what you can for Jimmy.