Thats exactly how they have done it for 25 years.
Its not the full 11 Million, they reset his salary to the 7th year minimum of 930K. Then the other $10,070,000 is converted from salary into a bonus and amortized over the remaining four years of his contract. So rather than Martin having a salary cap charge of 11 Million in salary, the current year becomes a cap charge of 930K in salary and one fourth of that 10.07 Million bonus as the cap charge for his restructure bonus for the current year. The other fourths are added to each of the next three years.
Teams will often add phony voidable years to the contract to spread it out over 5 years if they want even more cap space.
So Martin's cap charge would go from 11,000,000 to 3,447,500. That's a difference of 7.552,500.
Martin gets the money upfront and earns interest or cap gains by investing it now instead of getting it weekly. Dallas gains $7,552,500 in space under the cap.