While Sundar Pichai’s star at Google (GOOG) rises, Andy Rubin’s is falling, as the former Android founder and guru is leaving the company to launch an incubator for hardware product startups.

The Wall Street Journal first reported Rubin’s exit, which subsequently was confirmed by chief executive Larry Page.

“I want to wish Andy all the best with what’s next,” said Page in a statement. “With Android he created something truly remarkable—with a billion-plus happy users. Thank you.”

Google bought Android in 2005 along with founder Rubin and he helped the mobile OS to become the world’s most popular smartphone platform, as evidenced by its current 85 percent market share.

Rubin, who stepped down as Android boss in March 2013 in a move that saw Pichai add the mobile OS to his Chrome OS and Google Apps responsibilities, had been leading Google’s robotics effort, which included a number of related acquisitions such as Boston Dynamics in December 2013, Schaft, Meka Robotics and five others.

His exit appears to have caught Google somewhat by surprise, considering his robotics work at the company was ongoing and had yet to come to fruition. However, a Journal source said Rubin’s entrepreneurial spirit may have gotten the best of him, noting he was dealing with some constraints on his activities at the company.

Google hasn’t said publicly why Rubin left and he hasn’t said anything either.

A Google spokesperson told the Journal that the vendor will continue to invest in robotics despite Rubin’s departure. James Kuffner, a Google research scientist and current member of its robotics team, will take Rubin’s place running the unit, the Journal reported. Kuffner is said to be well-versed in robotics, previously working on human-like robot technology for some 20 years, including five years on Google’s self-driving car project.

In a new reorganization spearheaded by Page, Pichai now is boss of all the company’s core products, including commerce and ads, Google+, infrastructure, maps, research and search.