Mitchell Starc has become the first player to take the provocative step of aligning with a rival to one of Cricket Australia's protected sponsors as the sport's industrial war rages on.

The towering quick, arguably the best fast bowler in the world, is one of Australian cricket's most marketable commodities and more than a week after 230 players fell out of contract he has been among those in hot demand.

Now, it can be revealed that Starc has signed a sponsorship deal with an Audi dealership that may lead to consternation at CA, which has included fellow car company Toyota among its so-called protected sponsors for the 2017-18 season.

Players were cautioned by CA team performance boss Pat Howard just prior to becoming free agents on July 1 that they jeopardised a future contract with CA if they signed "unapproved endorsements" before a new memorandum of understanding between the governing body and the Australian Cricketers' Association was agreed.