Jack Tretton will step down this month as chief executive of Sony Computer Entertainment America, the company announced Thursday.Tretton's departure as head of the key US division comes as the Japanese entertainment and consumer electronics titan increasingly counts on its PlayStation division to lead a charge back to financial glory.Tretton will step down effective March 31, turning the job of Sony Computer Entertainment America chief over to Shawn Layden, currently chief operating officer of Sony Network Entertainment International, according to a statement.The change in leadership resulted from a mutual agreement not to renew Tretton's contract, Sony said.Tretton has been with SCEA since it was created in 1995 and was credited with playing pivotal roles launching each generation of PlayStation as well as the consoles' online entertainment service and handheld game device Vita."Working at SCEA for the past 19 years has been the most rewarding experience of my career," Tretton said in a released statement."I leave PlayStation in a position of considerable strength and the future will only get brighter for PlayStation Nation."Earlier this week, announced it has sold more than six million PlayStation 4 consoles since the video game system debuted in November.Sony said that the global sales figure includes 370,000 PS4 consoles snapped up in Japan since they launched in the global company's homeland on February 22.Industry trackers have the PS4 strongly outselling the new-generation Xbox One that US rival Microsoft fielded in November.PS4, Xbox One, and Nintendo's Wii U are fighting to be at the heart of digital home entertainment at a time when consoles are under intense pressure to prove their worth as people increasingly turn to smartphones or tablets for games and videos. Sony's gaming division has emerged as a potential savior for the once-mighty giant, which is struggling to reinvent itself in the digital age, having been left in the dust by nimbler rivals like South Korea's Samsung.Reports surfaced last week saying that Sony will sell properties at a prestigious Tokyo site where it had its headquarters for six decades, as the once-world beating firm struggles to improve its bottom line.Sony warned last month that it would book a $1.08 billion loss in the fiscal year to March as well as cut 5,000 jobs and exit the stagnant PC market. The embattled company said in January last year it was selling its US headquarters in Manhattan for $1.1 billion.