; or (B) four years. (2) Waiver (A) In general The Secretary of the military department concerned, in coordination with the Director of the Defense Health Agency, may authorize a tour of duty of an individual as a commander or director of a military treatment facility of a shorter length than is otherwise provided for in paragraph (1) if the Secretary determines, in the discretion of the Secretary, that there is good cause for a tour of duty in such position of shorter length. (B) Case-by-case basis Any determination under subparagraph (A) shall be made on a case-by-case basis. 714. Expansion of strategy to improve acquisition of managed care support contracts under TRICARE program Section 705(c)(1) of the National Defense Authorization Act for Fiscal Year 2017 ( Public Law 114–328 ; 10 U.S.C. 1073a note) is amended, in the matter preceding subparagraph (A), by striking , other than overseas medical support contracts . 715. Establishment of regional medical hubs to support combatant commands (a) In general The Secretary of Defense shall establish not more than four regional medical hubs, consistent with the defense health regions established under section 712 of the John S. McCain National Defense Authorization Act for Fiscal Year 2019 ( Public Law 115–232 ), to support operational medical requirements of the combatant commands. (b) Timing Establishment of regional medical hubs under subsection (a) shall commence not later than October 1, 2020, and shall be completed not later than October 1, 2022. (c) Leadership Each regional medical hub established under subsection (a) shall be led by a commander or director who is a member of the Armed Forces serving in a grade not higher than major general or rear admiral and who shall be— (1) selected by the Director of the Defense Health Agency from among members of the Armed Forces recommended by the military departments for service in such position