"I can confirm he's leaving Yahoo effective tomorrow," a Yahoo spokesperson told Business Insider. "We aren't commenting further."
Yahoo created the brand new position of Editor-in-Chief for Singh, who was poached from his managing editor position at Huffington Post in 2011. Prior to that, he created CNET News.com in 1996.
In addition to announcing De Castro's exit, Mayer's first major hire after taking over the company, an internal memo (obtained yesterday) to employees also announced restructuring within the company, to include the media and editorial unit being taken over by CMO Kathy Savitt.
Swisher writes:
Appointing a marketing person to be in charge of editorial is probably enough of a reason for many journalists to run screaming from the building, but it's not clear what prompted Singh's exit. In addition, Savitt has a very mixed reputation - and this is me being polite - inside Yahoo.
At this point, Singh's departure right after De Castro could be just a matter of coincidence, but the timing will likely lead to plenty of speculation.