Christian Hackenberg doesn't know the details of what to expect under his new head coach.

Sure, he talked with James Franklin on the phone once or twice a few years ago when Franklin was trying to recruit him to Vanderbilt.

And he did meet Franklin this past Sunday for about an hour with his father, Erick Hackenberg, a former college quarterback, too.

The new playbook will come soon enough. Spring practices are barely two months away.

"He's a very personable guy," Hackenberg said of Franklin. "He's up front and honest and brings a lot of intensity to the room. He's very fiery. I can't wait to get on the field with him."

Here's what Hackenberg does know: Franklin and Bill O'Brien coached together under Ralph Friedgen at Maryland. Both are considered offensive-minded coaches, innovators, even.

Plus, Franklin played quarterback at Division II East Stroudsburg University.

"Coaches who played quarterback have been there and done that," Hackenberg said. "They've seen everything that you've done. They've been through almost every situation you've been through.

"I'm excited to be able to work with him and his expertise. He understands."

Almost surely, Hackenberg knows this, as well: Vanderbilt's Ricky Rahne will be his new quarterbacks' coach and Josh Gattis will be following Franklin to Penn State, as well, to coach receivers. Both assistants announced their destinations Wednesday on Twitter.

It's a lot of change for the Lions' marquee player, who was O'Brien's first Penn State recruit and has quickly become a leader on and off the field. Under O'Brien's tutoring, Hackenberg just missed being the Big Ten's second-leading passer and surely is the league's top up-and-coming quarterback entering his true sophomore season.

In many ways, O'Brien convinced Hackenberg to pick Penn State. But Hackenberg said his abrupt departure for the NFL didn't sway him.

"I think that when you finally get up on campus and build relationships with guys and people up here, it's tough to leave. It's a special place. People don't really understand that until they are a part of it."

Even Hackenberg like most every one of his teammates has only positive things to say about O'Brien.

"It's a business. He had to do what was best for his family. At the end of the day, that comes ahead of everything. I wish him luck and I can't thank him enough for what he did for me and this team and this program. That's what people should be focusing on."

Moving forward, Hackenberg not only will work closely with Franklin but also Rahne, a former college quarterback at Cornell.