[Gangrene]

Offering franchise money to Keller suggests that he is worth top five tight end money. When healthy Dustin Keller is good but not near an average top five tight end in the NFL.
Conversely, despite his poor blocking skills we have had incredibly p*ss poor tight end play over the last twenty or so years that I remember of Jets football. Looking at the current market for tight ends it looks like he is worth at least four to five million a year. I doubt the Jets can afford that and someone out there will likely offer him closer to six a year.

Putting on my Jets GM hat, if we were to somehow clear the cap space, I would offer him 4.5 million a year over four years guaranteeing eleven million.

I doubt Keller would take it but to me that's about as far as I would go.