Washington (AFP) - President Barack Obama on Friday will announce his choice to replace Chuck Hagel as Pentagon chief, the White House said.Favored for the post is Ashton Carter, a former deputy defense secretary under Leon Panetta from October 2011 to December 2013.While stopping short of confirming the pick, the White House has hailed Carter's "detailed understanding" of the Pentagon's inner workings, and recalled that the Senate had unanimously confirmed his nomination as the Defense Department's number two in 2011.However, said White House spokesman Josh Earnest: "It's actually the president's nominee, and he will announce it tomorrow."Hagel, the outgoing Pentagon chief, announced his resignation last month.