Jeff Hafley, a single-high 4-3 defensive coordinator.
They keep repeating this, I'm interested to see if runs single high often in the NFL, as he's also talked about the importance of two deep shell.
Also... if he wants to run single high Safety, then the Packers need to get a true FS (or two).
PFF seems to suggest they believe the top 3 Safeties will be Franchised tagged, so I'd be looking at Safeties Xavier McKinney and Jordan Fuller.
Jordan Fuller would be an interesting one to look out for. Fuller went to Ohio State where he had Hafley as his defensive coordinator, and was drafted by the Rams, and LaFleur's Falcons drafted his brother Devin Fuller.