Partially correct. His overall contract was not front-loaded (I mis-spoke), but his signing bonus was. It's not a flat $5M per year. He got $6.67M annually for his first three years and starting this year, it's $2.5M annually for the rest of the deal. (
per Spotrac) Overall, that brings down what he costs against the cap, but he is still an expensive player.
The primary reason I care less about his deal now is that A) the worst of it is over and B) there aren't so many years left that he's unmoveable. A couple years ago, there was absolutely no way to move his deal. Now he's productive enough and there's a small enough chunk of money left that the Cubs could flip him for another bad contract that's easier to dump or eat a chunk of his money and send him away if that's what they want. There's $96M left total on his deal after this season.