"David has apologised to all Uber employees for a remark that was totally inappropriate and against the new culture we are building at Uber," Huffington said in a statement.
The incident came as Uber sought to move past a leadership crisis that has led to the departure this week of chief executive Travis Kalanick, as well as his close ally and confidante, Emil Michael, a senior vice president at Uber.
Kalanick's return date is not specified, and his responsibilities will undergo "review" to possibly shift some duties to other executives. He also faces the likelihood of reduced clout on the board, which is adding new "independent" members and creating an oversight committee to monitor efforts to improve corporate ethics and diversity.
"The ultimate responsibility, for where we've gotten and how we've gotten here rests on my shoulders," Kalanick wrote in an e-mail to employees. "There is of course much to be proud of but there is much to improve. For Uber 2.0 to succeed there is nothing more important than dedicating my time to building out the leadership team. But if we are going to work on Uber 2.0, I also need to work on Travis 2.0 to become the leader that this company needs and that you deserve."
In describing reasons for the leave, Kalanick also cited the death of his mother and serious injuring of his father in a boating accident last month, saying, "I need to take some time off of the day-to-day to grieve my mother, whom I buried on Friday, to reflect, to work on myself, and to focus on building out a world-class leadership team."