Another provision of the new deal stipulates that contracts for players selected in the second through seventh rounds of the draft will not exceed four years.
But the league rejected that contract on July 31, claiming Miami exceeded the salary cap to sign Howard.
Six contracts have already exceeded that package and one has matched it.
The law would apply to contracts for goods and services exceeding $10,000 and capital-project contracts exceeding $15,000.
Mr. Gold said the costs of completing that contract could exceed $10 million.
Fixed-term contracts may not exceed three years for first level executives and five years for executives.
But some contracts exceed that amount, and Adu's will be the highest, perhaps $500,000 a year or so.
The contract will probably exceed $8 million for three years.
That contract exceeded the five-year, $34 million deal the Diamondbacks gave shortstop Jay Bell, who will play next to Williams.
An annual contract, for one dog and his handler, can exceed $200,000.