News site All Things D, citing "multiple sources close to the situation," reported Mattrick will potentially become CEO of the struggling online social gaming company Zynga, with the executive set to swap Halo for Words with Friends.
The site speculated an announcement could come as soon as today once the markets close in the United States, and shares of Zynga are currently up 11.87% at $3.10.
The move would mean founder Mark Pincus would step down as CEO of Zynga, as the company struggles to turn around its recent missteps.
Microsoft, with Mattrick as its head of interactive entertainment, originally demanded daily online authentication checks for the console and said it would limit the ability to resell used games.
Mattrick joined Microsoft in July 2007, following stints with Distinctive Software Inc. and video game giant Electronic Arts.
Zynga itself is struggling to convert its Facebook users to mobile gamers, and last month Zynga laid off more than 500 employees and closed several offices.
"The scale that served us so well in building and delivering the leading social-gaming service on the Web is now making it hard to successfully lead across mobile and multiplatform, which is where social games are going to be played," said founder Mark Pincus at the time of the announcement.