From what I recall, even before Saban retired, Byrne knew it was a likely possibility (based on discussions with Saban at the time). Bryne therefore was doing homework and getting things in order quietly, just in case Saban stepped down. Byrne supposedly spoke with Lanning (and Sexton) briefly in Texas (I think at the national championship game) a week or so before Saban’s retirement. He learned then that Lanning wasn’t hireable at the time… in part due to Lanning not wanting to leave, in part due to his buyout being an issue. But he used the opportunity with Lanning to ask about DeBoer who Lanning had competed against. DeBoer was already a massive target, evidenced by the fact that Sexton and him slow played UW on a contract extension. Anyway, Byrne got good feedback from the talk and it helped solidify his #1 target. Then when Saban made his decision to retire, things moved quick.