You are assuming that TruJ would prefer to take less money for 2017 in exchange for a long term contract. I think that assumption is beyond questionable.
Would you do that? I wouldn't necessarily do that unless the contract was for big time guaranteed money and I doubt he'd get that at this point.
Besides, the chances that someone would give him even $12 or $13 mil the first year is also questionable. He certainly didn't have a great year in 2016. If you look around the standard FA deal is 2 years.
And he is plenty young enough to play what is essentially a one year deal for 2017, and then look for a longer term contract in 2018.