The Trump administration is expected to name Vice Adm. Robert Harward as national security adviser, a senior White House source told Fox News Wednesday.

The move comes after Michael Flynn resigned from the role Monday after it was revealed he had discussed U.S. sanctions with the Russian ambassador, although he told Vice President Mike Pence he had not.

Harward, a former Navy SEAL and a former deputy commander of CENTCOM, served under Defense Secretary James Mattis, which would make him a good fit on the National Security Council.

Harward has also served on the National Security Council in the past, under President George W. Bush, and commissioned the National Counter Terrorism Center.

After retiring from the Navy in 2013, Harward became chief executive officer for defense and aerospace giant Lockheed Martin in the United Arab Emirates. Trump has recently been in very public negotiations with Lockheed over the cost of its F-35 fighter jet program.

White House sources describe him as “the toughest guy in

the SEALs,” and a “real rock.”

The senior White House source told Fox News that the deal isn’t quite finalized yet, but is expected to be very soon and that he could be at work by Friday.

Fox News’ John Roberts and The Associated Press contributed to this report.