(Reuters) -Sam Altman and OpenAI's board have opened discussions to bring back its former CEO, and the startup's backer Microsoft is discussing governance changes it plans to request from the board, Bloomberg News reported on Tuesday, citing sources.

Talks are taking place between Altman and at least one board member, Quora CEO Adam D'Angelo, Bloomberg said in a report citing people familiar with the matter.

Altman could return as a director on a transitional board and the talks also involve some investors of the artificial intelligence startup.

The ChatGPT owner fired Altman in a surprise move on Friday and before the weekend was over, OpenAI investor Microsoft hired him and Greg Brockman, another co-founder of the startup.

But things appeared fluid, as Microsoft CEO Satya Nadella told media on Monday "irrespective of where Sam is, he's working with Microsoft" and that governance at OpenAI needed to change.

The changes Microsoft is planning to ask OpenAI's board for may include an increase in the size of the board and a boost to the experience level required for members, Bloomberg said.

Other than Quora's D'Angelo, OpenAI's four-person board consisted of Tasha McCauley, Helen Toner and OpenAI chief scientist Ilya Sutskever as of Friday.

Microsoft's deal with OpenAI requires the startup's board to seek Microsoft approval for a merger, and the software giant will look to shore up those protections, Bloomberg said.

OpenAI did not respond to Reuters requests for comment.

Altman's ouster started a revolt at the company. Nearly all of its more than 700 employees threatened to quit in a letter demanding the resignation of the board and reinstatement of Altman and Brockman.

Nadella has said he was open to staff staying at OpenAI or coming to the Windows maker.

OpenAI interim CEO Emmett Shear has told people close to the company that he does not plan to stay if the board cannot clearly convey the reason for Altman's ouster, the Bloomberg report said on Tuesday.

Some investors in OpenAI are considering suing the company's board, sources told Reuters on Monday, on worries that they could lose millions of dollars they invested with the potential collapse of the hottest startup in the rapidly growing generative AI sector.

(Reporting by Akash Sriram and Chavi Mehta in Bengaluru, and Sayantani Ghosh in San Francisco; Editing by Devika Syamnath, Arun Koyyur and Sonali Paul)