I think there are three reasons why Chubb signed this deal beyond a hometown discount or “winning team” discount.
1) this gives Chubb a longer-term guarantee that he lacked while making $11mil more in base salary this year than last. That’s a pretty substantial increase.
2) Chubb has a history of major injuries. Getting $20m guaranteed sets him up for life in a way that one more “rookie contract” season and two years of franchise tags would not. One injury during that period and Chubb’s future is bleaker.
3) Finally, by only being three years, it lets Chubb get paid AGAIN if he stays healthy. The total pro carry number RBs usually decline at is 1,500, and I don’t think Nick is even halfway there. This means it is statistically plausible that Chubb could get another large payday in three more years.
It is a “team friendly” deal, but it also makes financial sense for Nick. It’s one of those rare deals where both sides can be happy with their absolute gain.