Turns out Mannion directly talks about that:
“I think when you look at it kind of from the outside looking in, it’s somewhat similar concept wise, but there’s obviously [an additional] set of details that coach Boras and coach Groh have changed,” Mannion said. “And, honestly, you’re always in the process of learning. Even at Oregon State — I was there for five years, even by my fifth year, you’re always learning something new.
“So it’s not as though you’re going to go through an offseason where there’s nothing to be learned. There’s always something to learn,” Mannion added. “But certainly with coach Boras having the offseason to look at it, coach Groh coming in — there are differences. And I think it’s been good for us. It’s been really good.”
link: http://theramshuddle.com/topic/mannion-taking-advantage-of-otas/#post-45310
So both Boras and Groh have worked on tweaking the offense. We don’t know how or how much.
I have seen some try to attribute this all to Groh, but, that doesn’t make any sense…Boras is the coordinator, and he basically “runs the committee” and okays any changes and has (of course) input of his own.
I think the “Groh did it” routine comes from people who believe the poor showing of the offense last year was due primarily to the scheme, and that Fisher finally brought in someone with the right ideas.
I don’t think that view makes any sense.
First, I don’t think the offensive problems last year were from the scheme–it was execution, and the combo of a young then injured OL and a melted down starting qb. Either way this is the first time Boras has the offense as his own in the off-season, and he’s going to modify it to suit his vision. It’s Boras’s offense and he is apparently working with Groh to tweak things in the passing game. Probably the running game is being tweaked too.