VA Secretary Robert Wilkie said Wednesday that he fired Deputy Secretary James Byrne for failing to "jell" with the rest of the leadership team and stressed that the dismissal was not related to an alleged sexual assault case at the Washington, D.C. VA Medical Center.

"It was a simple business decision" to sack Byrne, who had been the No. 2 at the Department of Veterans Affairs for five months, Wilkie said, adding that there was "nothing personal" in the abrupt move to terminate him "effective immediately" on Monday.

Byrne left the Marine Reserves as a lieutenant colonel and previously had served as the VA's general counsel.

"It was in the best interests of the organization" to remove him from his deputy secretary post, Wilkie said at a National Press Club news conference.

Wilkie did not give additional details on what made Byrne a poor fit for the team, but noted he wished him well and called him a "man of great distinction."

Related: Abrupt Firing of VA's Top Deputy Gets Mixed Reaction from Congress

Wilkie also said it was "categorically untrue" that Byrne's firing was linked to the ongoing dispute over the claim of sexual assault filed by Navy Reserve Lt. Andrea Goldstein, a staffer on the House Veterans Affairs Committee.

Goldstein had alleged that another veteran rubbed up against her and made lewd suggestions at the Washington, D.C. Medical Center last September.

Byrne's name had surfaced in the case, as he participated in conversations with VA Inspector General Michael Missal about it. Wilkie drew a rebuke from Missal when he described the case as "unsubstantiated" in a letter to California Rep. Mark Takano.

"Reaching a decision to close the investigation with no criminal charges does not mean that the underlying allegation is unsubstantiated," Missal said.

At the news conference, Wilkie stopped short of issuing an apology, but said he met with Missal Tuesday night to iron out differences. He also said he would be in contact with Takano on the Goldstein case "to make sure her needs are taken care of."

-- Richard Sisk can be reached at Richard.Sisk@Military.com.

Read More: Russian Submarine Activity Has Picked Up in Atlantic, Navy 3-Star Says