When it was formed 11 months ago, Ad Age questioned whether Chevy's "historic" agency setup -- a cooperative owned jointly by holding-company rivals Omnicom Group and Interpublic Group of Cos. that would service Chevrolet's massive global creative account -- could really work.

Now we've got an answer: Nope.

Executives said that talks are underway between General Motors and Commonwealth execs to put McCann in the driver's seat at the agency and turn over all global ad responsibilities for Chevy to that shop. That would effectively cut out Omnicom's Goodby Silverstein & Partners from the equation. GM, Goodby and McCann declined to provide comment to Ad Age and Goodby co-founder Jeff Goodby said he's not gotten any word from his client about discussions underway that may negatively impact his agency. But numerous Detroit executives have been buzzing about the ill-fated state of this setup, predicting that the end is near for Omnicom Group-owned Goodby Silverstein's role as a part of the structure.

You could say that such a move is all part of GM's quest to find a new road --one that takes it far, far away from the haphazard marketing decisions that were made under former CMO Joel Ewanick, who was ousted last July. He left amid controversy over a botched sports marketing deal and use of company funds. Yet Mr. Ewanick has had little trouble reemerging in the auto sector. He is currently serving as a special advisor to the CEO at Fisker Automotive, and been attending car industry events again. Earlier this week he was tweeting pictures from the Geneva Auto show, and was recently writing about environmental marketing strategy for a blog.

With Mr. Ewanick in the rear-view mirror, General Motors' interim head of marketing for the past six months, Alan Batey, has increasingly been undoing moves made by his predecessor. He scrapped the "Chevy Runs Deep" tagline criticized by consumers and replaced it with the new ad theme, "Find New Roads." He earlier lifted one piece of business out of Commonwealth -- Silverado trucks -- and handed the business to Publicis Groupe's Leo Burnett. Many have been wondering whether cutting Goodby Silverstein would be the next move, given that Mr. Goodby is a longtime friend of Mr. Ewanick.

In an interview with Ad Age in January, Mr. Batey insisted that he's happy with the Commonwealth structure. One person close to the situation speculated that Commonwealth would continue as Chevy's global agency, but going forward it would essentially just be fueled by McCann globally. The person noted that these moves are part of GM reverting to simplicity in its marketing strategy. The alignment of all truck advertising at Leo Burnett was one example, and if Goodby Silverstein is removed from the Commonwealth structure, it would mean Chevy has a single global agency rather than different shops handling U.S. versus global work. It also jibes with a key goal of GM CEO Dan Akerson, who wants to elevate the Chevy brand into a true global player.

It's worth noting that Tim Mahoney, who is joining GM as global head of Chevy advertising after two years at Volkswagen of America, is used to working with a single shop, Interpublic's Deutsch.

If indeed the Chevy business drives away from Goodby Silverstein, it will be a tough thing for the shop to manage to ensure that the hundreds of employees who have been working on the business will be taken care of. It's also worth noting that the agency put enormous resources behind the Commonwealth arrangement, and to the degree that didn't work, it wasn't for a lack of trying or infighting between the shops. As Mr. Goodby said at the outset of the venture: "Listen, the agency thing, the network thing, that's gonna be checked at the door."

For McCann, which in recent years has struggled with management turnover and client losses, it would mean a hefty chunk of additional business brought in at the outset of new CEO Harris Diamond's tenure. It's a testament to the work that McCann top creative Linus Karlsson has been doing on GM; he was originally brought in to shake up the creative product at the agency overall, but over the last several months has been hyper-focused on the automaker and is said to spend a lot of time in Detroit.

It's only going to get busier. Last year global Chevy sales hit a record 4.95 million units across 140 countries and represented 54% of GM's global sales. And Chevy is embarking on the busiest vehicle-launch schedule in the brand's 102-year history. It will roll out 13 new or redesigned models in the United States this year, including its next-generation Silverado pickup, and plans another dozen rollouts overseas.