In the not-so-distant past, coaching changes for the Penn State Nittany Lions football program were rarely thought about or even considered possible. If Joe Paterno was one thing, it was consistent.
In fact, Paterno's staff saw just one change during his final seven years at Penn State, when safeties coach Brian Norwood left in 2007 to become the defensive coordinator at Baylor. That was after seven seasons in Happy Valley.
Nittany Nation is now being introduced to a whole new world involving coaching turnover.
Bill O'Brien has been on the job just shy of two years now and has seen more changes than the previous regime did in the previous decade.
Following the 2012 campaign, defensive coordinator Ted Roof left Penn State for the same job at Georgia Tech, where Roof was an All-American defensive back in college. O'Brien quickly promoted defensive backs coach John Butler to his first coordinator job and brought on Anthony Midget to fill the spot on the staff.
Last week, Penn State released a statement that quarterbacks coach Charlie Fisher and linebackers coach Ron Vanderlinden have "resigned to pursue other opportunities."
The loss of Fisher is strangely intriguing.
Many believe that O'Brien does the majority of the quarterback coaching at PSU. If that's true, Fisher's replacement could have a slightly different role. An offensive coordinator is possible, though it's hard to imagine O'Brien relinquishing play-calling duties.
A special teams coach is another potential option, but don't rule out a new quarterback coach with a more versatile recruiting role.
The Vanderlinden loss is, at best, less intriguing. Predictably, Butler had some rookie moments while learning on the job in is first year as a coordinator.
However, he was fortunate enough to be surrounded by guys like Vandy and defensive line coach Larry Johnson, who have around 30 years of college coaching experience between them and are two of the top coaches in their respective roles.
Hopefully, Butler is a fast learner.
In just two years, Penn State has lost what may have been its two best defensive minds in Roof and Vanderlinden.
So what happens now? It's impossible to know before those spots have been filled.
O'Brien did a terrific job of assembling his staff upon arriving in State College. The hiring of guys like Stan Hixon and John Strollo has been instrumental both on the field and on the recruiting front.
Because of that, O'Brien has earned the benefit of the doubt. Still, replacing Vanderlinden could prove nearly impossible.
This is nothing new in the world of college coaching. Florida recently fired its offensive coordinator and offensive line coach. Notre Dame lost its offensive coordinator when he took the head coaching job at Miami (OH) and Steve Sarkisian left Washington for USC and was replaced by Boise State's Chris Peterson.
Coaches don't stay in one place very long.
The good news is O'Brien knows that and won't be afraid to reach out to anyone on any staff who he thinks can come in to Lasch and fit the needs he has on his coaching staff.
Maybe Penn State is going to change things schematically. Maybe Vanderlinden got a better offer. Maybe O'Brien decided he can better utilize Fisher and Vandy's spots on his staff.
The only thing for certain is that it won't be seven years before the next coaching change in Happy Valley.