White House physician Ronny Jackson was surprised when President Donald Trump tapped him to run the Department of Veterans affairs and hesitated to accept the nomination, the Washington Post reported Thursday.

Senior White House officials who spoke with the Post said that Trump’s aides talked with Jackson in recent days to gauge his interest, but he was wary about taking on “such a big job,” according to the Post.

But Trump was adamant about Jackson and told senior staff on Monday that his personal doctor was his No. 1 choice, according to the Post. The White House reportedly had planned to announce on Wednesday that Shulkin was leaving the department and would be replaced by Robert Wilkie on an interim basis, but Trump preempted everyone with his tweet, saying Shulkin was out and Jackson was in.

….In the interim, Hon. Robert Wilkie of DOD will serve as Acting Secretary. I am thankful for Dr. David Shulkin’s service to our country and to our GREAT VETERANS! — Donald J. Trump (@realDonaldTrump) March 28, 2018

Shulkin’s ousting has been widely speculated for weeks after reports surfaced that Shulkin and his staff acted inappropriately in order to secure government funding for his wife to accompany him on a trip to Europe. The White House was also reportedly frustrated with Shulkin’s openness with the media and his claims that political appointees within his department were working against him.

The nomination of Jackson, an active-duty rear admiral who has served as the White House physician for the past three administrations, has been criticized because of Jackson’s lack of management experience. The VA is the second largest department in the administration, serving more than nine million veterans a year.