Charles "Chuck" Rozwat, Oracle's executive VP of product development, who reports directly to CEO Larry Ellison, is taking a leave of absence. Thomas Kurian, Oracle's senior VP of product development, will take over Rozwat's duties.

The management change comes as Oracle prepares to launch its next-generation Fusion applications, which have been in development for years and were designed to represent the best of dozens of Oracle acquisitions.

Karen Tillman, VP of communications at Oracle, says the management change shouldn't affect the Fusion launch. "Thomas [Kurian] has been leading the Fusion application delivery, so I don’t see a major change there, or any real big impact," Tillman said.

The change, however, puts Kurian in position to become one of the most powerful executives at Oracle -- if not the second-most-powerful after Ellison -- particularly if the Fusion launch is a success. Kurian is a tough, no-nonsense executive who worked his way up through the ranks since joining Oracle in 1996.

Rozwat is taking the leave to pursue a master's degree in public policy at Harvard University. Rozwat said it was "time for a change" in an internal memo to employees that was obtained and posted Wednesday by blogger Dennis Moore, who worked at Oracle years ago and later as an SAP product executive.

"After 15 years at Oracle (following 17 years at Digital Equipment) in software development, I have decided it is time for me to step away from my current role and broaden my knowledge and skills in another dimension," Rozwat wrote. He'll "take the next twelve months to gain a perspective different from my years developing software as part of the high tech, private sector world," Rozwat wrote, adding that it had been a "long-considered and difficult decision in many respects… ." His leave starts Aug. 1.

Rozwat called the departure a 12-month leave of absence, which was confirmed by Tillman. Yet parts of the memo read like a resignation letter. "It is impossible for me to express my gratitude to Larry for what his overall product guidance has meant to the product development organization and also the life changing experience it has been for me to be allowed to be part of his team," Rozwat wrote.

In a June 23 quarterly earnings call, Ellison said Oracle was "code complete" with Fusion applications. "We'll be announcing them later this year. Customers are trying them out, and we'll start delivering next year," he said.

It's been a long and dramatic road for Fusion app development. The apps are coming out a few years later than originally intended, and the former head of Fusion, John Wookey, left the company under unclear circumstances in October 2007. Kurian took over Wookey's role and reported to Rozwat. Wookey has since joined Oracle rival SAP, heading up that company's fledgling on-demand enterprise software unit.