Marcus Arroyo looked back on every play he called last year.

Oregon’s offensive coordinator found plenty to retain from a unit that ranked second in the Pac-12 Conference with 34.8 points and 427.2 yards per game and also a few pages of the playbook he plans to discard before quarterback Justin Herbert’s senior season.

“You take things that work and see what you can do, what you can work through,” Arroyo explained following Oregon’s second spring practice Tuesday. “There are a couple different schemes we like that fit us with Justin’s experience and a little more experience outside. Without giving it away, there are a couple things we will add wrinkles to. Maybe it was a B-list type thing, a secondary thing that was really good. If you look at the efficiency, it was good. We did it five times, lets do it 15 instead because that was a real good play. If we ran it 10 times and got five explosive plays, lets ramp it up and bump this down because the other thing is something we are banging our heads against.”

Arroyo has a binder that features clips from each game and analytics from the season when Oregon went 9-4, culminating with a 7-6 win over Michigan State in the Redbox Bowl.

“It is a pretty comprehensive, dialed-in approach on how we evaluate ourselves,” he said. “That’s always the best part of the offseason is after one year you go back and utilize the cut-ups we’ve got and find out exactly where things are. What you like and what approach we want to take. The next part of the offseason is to study what is out there, what trends and things you can do to make you better.”

Arroyo labeled the offseason process as “really, really thorough” and “ultra advanced.”

“You get into what is effective on first down with certain personnel in certain parts of the game,” he said. “How are certain parts of the game affected? How was this concept affected? How was the ball to this receiver in this concept and like any major business, if that is not working you find out where the hay is made. We were pretty good at this or this was smart. As coaches, sometimes we get hung on things and really like a certain thing, but why do we like it? If it wasn’t very good, then scrap it and go back and get another rep of this one.”

Arroyo returns every starter on his side of the ball except wide receiver Dillon Mitchell, who declared for the NFL draft following his junior season.

The offensive staff was shuffled when receivers coach Michael Johnson left for Mississippi State and was replaced by Jovon Bouknight from Utah State. Arroyo was part of Bouknight’s job interview and recalled watching the Aggies play last year against Michigan State while he was preparing to face the Spartans in the bowl game.

Quarterback Cale Millen and wide receiver Josh Delgado are among the freshmen who enrolled early to practice in the spring when the Ducks will hold five practices through Saturday before taking a two-week spring break.

“In this first block of practices before spring break, No. 1 we want to get the new staff and new guys acclimated and truly give yourself an evaluation,” Arroyo said. “A lot of times what you do is try to give those guys too much too early and you don’t really see them because they are thinking too much. We have done a good job in the past few years making sure they can comprehend so we can evaluate guys and get some staff guys caught up to work on core stuff early.”

Millen has been slowed by a foot injury but is practicing behind Herbert and redshirt freshman Tyler Shough.

“He’s a junkie in office all the time taking good notes,” Arroyo said. “Football is real important to him and that is what you want.”

Arroyo and Herbert are entering their third season together in the quarterbacks room.

“The key for us is we are comfortable around each other, but you can’t get too comfortable,” said Arroyo, noting how the two switched up an old footwork drill in practice Tuesday. “My approach his senior year is to make sure this experience is the best it can be for him. You only get one shot at this age, at this place playing Power 5 football. It has to be fun, it has to be something you get a lot out of. I want to make sure every day for him he is thinking ‘I’m excited to be here’.”

When Mitchell turned pro, Herbert was left without a returning receiver who had 500 yards last season, but Jaylon Redd, Brenden Schooler and Johnny Johnson III all started at times last year. Delgado will be joined by three other freshmen in the fall and graduate transfer Juwan Johnson will arrive from Penn State.

Arroyo pointed out redshirt freshmen Bryan Addison and JJ Tucker among the receivers showing improvement in the spring.

“I think because the older guys stepped it up, the younger guys said ‘OK, here we go’,” Arroyo said. “That is what you want to see. Shrinking the gap from the most committed to least committed and most experienced to least experienced. Guys are starting to push to the top and that is exciting to see even after two days.”