Case Keenum might know the new playbook and schemes installed from head coach Kevin Stefanski better than any other Browns player.

That's not a slight against anyone on the Browns offense, which has spent the last several months running endless drills, both virtually and on the field, to learn every detail of Stefanski's playbook. The wide-zone schemes Stefanski incorporated into the playbook contain new wrinkles for nearly every player, no matter the position.

Keenum, however, had a head start on the philosophies of the playbook — he played under Stefanski as a starting quarterback when he was with the Minnesota Vikings in 2017. Stefanski was Keenum's quarterback coach at the time, and he was quick to sign Keenum as a free agent this offseason.

"There are some similarities with a lot of things with the offense, but it is new," Keenum said Wednesday in a video call with local reporters. "I think it's a very quarterback-friendly offense from just the things I have seen in the past. It's 2020 Browns. I think we're all learning. We're all growing. We all bring different things to the table, but this is a new year, a new team. I'm excited."

Keenum's role with the Browns is simple: help Baker Mayfield become the best quarterback he can be and, of course, be ready to play at a moment's notice.

His most important day-to-day duties are to help answer questions Mayfield might have about certain reads, audibles or formations. On gamedays, Keenum will be ready to dissect every sequence with Mayfield with a tablet in hand.

Keenum knew those would be his core roles when he signed a three-year deal with the Browns in March. He's devoted himself to helping Mayfield and the rest of the quarterbacks — Garrett Gilbert and Kevin Davidson — ever since he signed, and he was one of the players who made a visit to Mayfield's home in Austin, Texas, for an in-person offseason workout.

"That is a huge part of why I was looking forward to being around Case was that he was in this system, so I can hear his thoughts on how it is taught and how he reads it," Mayfield said in May. "He has been in a lot of systems, as well. Just hearing how he visualizes certain things and certain reads has been great."

Keenum believes the offensive installs are perfect for Mayfield's skills and will increase the number of big play opportunities. He knew Mayfield had a strong arm before he saw him throw in person, but Keenum has seen through the first couple weeks of training camp just how quick Mayfield can throw a football.

He knows a strong quarterback is needed to thrive in the offense, which features lots of play-action passes that often lead to deep balls or quickly throwing the football into a tight window.

"He has a stronger arm in person than he does on film, and he made some really good throws on film," Keenum said. "He is a gamer and can make some big-time plays and some big-time throws."

When Keenum sits with the other quarterbacks for film breakdowns, the discussions cover a variety of critiques. Some are related to simple footwork technique and throwing reads, while others are about second- or third-down philosophies and play calls.

All of that, however, revolves around the playbook and schemes installed by Stefanski. In an unusual offseason, it certainly doesn't hurt to have a quarterback like Keenum — who has adapted to three new playbooks in the last three seasons — in that discussion.

"Case has been in a bunch of different systems, and I think he can apply a lot of those learned lessons in each of those into this system," Stefanski said. "I think with all of our players that have come from different places, the terminology may be different, but the general philosophy sometimes is the same on a given play. Case is an example where he can give good color to a certain concept and how it has worked for him in the past."

The process is still ongoing, but so far, the playbook has been given excellent reviews by each player asked about it. The roles for each position group are well defined, and each position — from the tight ends to the offensive linemen — have players with strengths catered to the needs of the wide-zone scheme.

That includes the quarterbacks group, and the fit extends beyond Mayfield. Keenum arguably has the strongest fit of any player due to his experience in the offense, and that should only help boost the play of Mayfield.

And if he has any questions or needs any assistance with the installations, Keenum will be there to help.

"There is a little bit of everything," Keenum said about the playbook. "Like I said, there is only one way to describe it, and that is '2020 Browns.' Hopefully, it will be on full display come weekends in the fall."