Facebook, which stopped using Google email and productivity applications inside the company a few years ago, is now mulling a switch back to the Google services for its employees, according to two people with knowledge of the discussions. Such a move would be an embarrassing setback for Microsoft, whose applications Facebook currently uses.

If it happens, the move would be more than a typical case of a company switching technology vendors. It would represent a significant reversal for Facebook CEO Mark Zuckerberg, whose aversion to the company's rival Google has been well known inside Facebook for many years. The switch is being considered as a way to soothe long-running frustrations among Facebook employees over Microsoft’s applications and others—like Salesforce’s Quip. But it may also suggest Google no longer represents the kind of threat Facebook once saw it as. Facebook, which has about 27,000 employees, is also considering moving its cloud storage to Google from Dropbox, said one of the people.