He would definitely improve the offensive line, I don't think there is any question about it.
I still think it's a matter of resources and Miami has invested more into the offensive line than anybody in the NFL . . . and signing Mathis limits their ability going into preseason and after cuts and definitely limits what they can roll over to next year when some huge cap hits take place.
Plus you have a guy who played in between 2 all pro players, is gonna be 34 years old and started showing signs of being injury prone last year. Maybe there are questions on how plug and play he'll be.
You start talking 7 and 8 million a year on a multi year deal for the guy, I can see where Miami would be hesitant.