I don't think anyone is counting on Brady to be good, or even available in 2018. I'm saying you won't know otherwise soon enough to justify the opportunity cost of keeping Jimmy.
Say Brady plays well to start the year but injures his throwing shoulder in week 11. Jimmy steps in and plays fine, makes the playoffs let's say. At the end of the year, Brady is rehabbing and plans to return. Jimmy wants a long term deal and a starting job. What do you do? Franchise and trade him? Franchise him and wait to see how Brady recovers, totally wrecking your cap and FA prospects? Let him walk?
The problem with keeping him is that even if you successfully hedge against a Brady health issue or decline, you may not be in a position to reap the benefits because of the decision window.
I think IF Brady noticeably declines in 2017, it's more likely to be a somewhat ambiguous or unpredictable situation going into the offseason, not a clear cut thing where you drop him and keep Jimmy. Sure, he could fall off a cliff or wreck his ACL in week 17 and you would be fairly sure you need Jimmy in 2018, but for every time that happens, you probably have two or three others where it's a much more marginal call, and you can't keep both.
Say Brady plays well to start the year but injures his throwing shoulder in week 11. Jimmy steps in and plays fine, makes the playoffs let's say. At the end of the year, Brady is rehabbing and plans to return. Jimmy wants a long term deal and a starting job. What do you do? Franchise and trade him? Franchise him and wait to see how Brady recovers, totally wrecking your cap and FA prospects? Let him walk?
The problem with keeping him is that even if you successfully hedge against a Brady health issue or decline, you may not be in a position to reap the benefits because of the decision window.
I think IF Brady noticeably declines in 2017, it's more likely to be a somewhat ambiguous or unpredictable situation going into the offseason, not a clear cut thing where you drop him and keep Jimmy. Sure, he could fall off a cliff or wreck his ACL in week 17 and you would be fairly sure you need Jimmy in 2018, but for every time that happens, you probably have two or three others where it's a much more marginal call, and you can't keep both.