They got a good deal. Given that he's already over 30, I'm a little surprised that the contract length wasn't more of a sticking point for Jackson, since he'll be way past the standard running back prime by the time this contract is done. But still, given the glut of FA RBs on the market, and the fact that he is coming off of a season-ending injury, I guess it makes sense for him, in a way. He came into the league late, and doesn't have very much wear on him, by NFL standards, so if he can maintain his production and stay relatively injury-free, then some team might talk itself into giving him another lucrative contract in a couple of years.