NSA Director Admiral Mike Rogers formally retired on May 4, 2018. He is now free to testify.
https://www.themarketswork.com/2018/05/05/a-quiet-hero-nsa-director-admiral-mike-rogers-retires/
Two Colleagues Contradict Brennan's Denial of Reliance on Dossier.
https://www.realclearinvestigations.com/articles/2018/05/14/2_colleagues_contradict_brennan_on_use_of_dossier.html