Game publisher Zynga Inc (ZNGA.O) announced Tuesday the departure of several senior executives, including Chief Operating Officer David Ko, as part of a management shake-up under new Chief Executive Don Mattrick.

The house cleaning comes a little more than a month after Mattrick, a former Microsoft Corp (MSFT.O) executive, was named Zynga CEO on July 3 and tasked with turning around the struggling game maker.

In a blog post published Tuesday, Mattrick, who replaced Zynga founder Mark Pincus, outlined a sprawling new management chart that named 13 executives from across the company as direct reports. None will report to Pincus, who now holds the title of chief product officer and owns a majority of voting shares.

Ten of the 13 executives reporting directly to Mattrick will be responsible for game development, the company said, signaling that Mattrick could be closely involved in the development of specific games.

"We are taking layers out of the executive rank to get senior leaders closer to important product initiatives," Mattrick wrote in his blog.

"Over the past month, I have had a chance to interact with a cross section of our employees and have been able to get a general sense of the caliber of people working here, the passion for winning and desire to get Zynga back to a strong leadership," Mattrick wrote. "Zynga is an amazing company and has tremendous potential for future growth."

Mattrick unveiled his new team 24 hours before Zynga's quarterly all-hands meeting on Wednesday, when he is expected to field extensive questions from employees for the first time about his strategic vision.

The company, which has suffered from sagging morale during several quarters of worsening performance and repeated waves of layoffs, is not expected to announce any additional staffing cuts on Wednesday, people briefed on the matter said.

Although Wall Street analysts have pushed the company to downsize, Mattrick played down the need for further cuts in July in his first public comments.

Mattrick has also asserted his authority by aborting the struggling game company's long-running effort to break into the real-money gambling business.

Ko, a Yahoo Inc (YHOO.O) veteran, had been swiftly promoted by Pincus, who gave him oversight of mobile games and later, purview over game development across the company.

Cadir Lee, the chief technology officer, and Colleen McCreary, the chief people officer, will also leave, Mattrick said.