Demetric Felton Jr. knows what it’s like to drown in a playbook.

During his rookie year with the Browns, the former UCLA star had to learn two positions as the NFL team alternated him at wide receiver and running back.

When he later made the Bengals’ practice squad, he had to figure out new terminology even though a lot of the concepts were similar to the Browns’. It felt like having to learn a language on the fly.

“I thought there, like, man, why don’t teams have a better system to onboard players because guys get traded all the time and have to be able to learn a lot of this information on their own and fast?” Felton told the California Post in an exclusive interview. “It’s stressful, and it costs opportunities; it can cost missed plays and lost games.”

That’s why Felton, a player known for zipping around the field, is speeding up the way others can learn their playbooks.

Having recently retired from playing to take a position as a player development assistant with the Browns, the 28-year-old is creating an online platform that allows players to immerse themselves in every aspect of the team’s scheme. The system measures their understanding of concepts through interactive demos and quizzes.

It will include different position-specific modules so that players can learn what they need to do in any given scenario. For instance, a running back can study his responsibilities in pass protection on various blitzes, bringing that knowledge with him to the practice field.

“If we can create ways for players to put themselves in that situation in an accessible way to mimic the type of stress that that situation puts them in,” Felton said, “we can then be able to make it instinct or a reflex on the field.

“Throughout my playing career, I always felt like I played the best when I wasn’t thinking and I just reacted, and when you’re confident that you know your responsibility, it allows you to play that way and that’s our whole goal with building this.”

Felton hopes his platform — which will be accessible via cellphones, iPads and laptops — can dispel the notion that football players who struggle to learn plays lack intelligence.

“I feel like the NFL and all football levels have a learning, teaching and player development problem,” Felton said, “and that we can be a lot more efficient with it through technology.”

Having completed a working demo for running backs, Felton plans to expand his platform for other position groups and believes it can eventually be used by teams at all levels and in different sports. He received positive feedback from a handful of NFL players who tested his platform at a recent MIT founders academy.

“They love the ability to mentally rep a full play while they’re studying,” Felton said. “It was reaffirming to know that this is a real problem that we can solve and that I’m the right person to solve it.”

Felton’s passion for his project gives him confidence that his transition from playing the game — he made 20 catches for 189 yards and two touchdowns in two seasons with the Browns — to helping others succeed was the right move.

“I’m not retiring because I don’t love this game,” Felton wrote on Instagram as part of his announcement. “I’m retiring because I know there’s a football player out there who needs me.”