From a be-leaguered advertiser...thanks for all the good work, you're fired.

Activision Blizzard has yanked creative duties for its "Guitar Hero" franchise from MDC Partners' Crispin Porter & Bogusky, tapping Omnicom Group's TBWA/Chiat/Day to market the games going forward.

The decision was made late last week, said Activision Blizzard's top marketer and chief creative officer, Brad Jakeman. He noted the move to TBWA, made without a review, wasn't because of dissatisfaction with Crispin's work but was "principally based on the outstanding work that [TBWA] did with us last year in launching 'Call of Duty: Modern Warfare 2,' which was one of the biggest entertainment launches of all time." (Though, leading up to launch, shops other than TBWA did a substantial bit of the advertising for the game.)

The game publisher claimed "MW2" brought in $550 million in software sales worldwide, enough to best the previous five-day global sales record holders from both the movie and gaming industries; "Harry Potter and the Half-Blood Prince" grossed $394 million in global box-office sales, and "Grand Theft Auto IV" snared $500 million.

But people familiar with the situation say the agency change was spurred in part because the Crispin work didn't deliver the desired brand positioning for the franchise. A spot released last fall for "Guitar Hero 5" that featured Hugh Hefner and Playboy Playmates playing air guitar was directed by Brett Ratner. It was one of a series of ads that spoofed a scene from the Tom Cruise movie "Risky Business" that also featured various sports celebrities and heavy-metal band Metallica. Crispin could not be immediately reached for comment.

Under Mr. Jakeman, Activision Blizzard assembled an all-star roster of agencies, including BBDO, Crispin, TBWA, Droga 5 and Toy. The majority of the work this year is expected to be handled by TBWA and Droga 5; TBWA will handle "Guitar Hero" and "Call of Duty," while Droga 5 will handle the marketing of yet-to-be-released titles that are likely to be unveiled in the run-up to the gaming industry's E3 Expo event in early June.

BBDO doesn't have any assignments scheduled for this year, Mr. Jakeman said, and the work that was being handled by Toy was for licensed properties such as "Wolverine," which doesn't have a launch this year either. Activision Blizzard's global media agency, WPP's Mediaedge:cia, remains unaffected by the changes.

According to Kantar Media, Activision spent about $84 million on domestic measured media in 2009, up slightly from $79 million in 2008