Pat Watson wasn't surprised to see Matthew Judon walk into his Advanced Placement psychology class at West Bloomfield (Mich.) as a senior six years ago. Watson knew about Judon's exploits on the football field and was aware of his aspirations after high school.

“He was a high-character kid. He wanted to challenge himself and better himself when he got to college,” recalled Watson, now the school's principal. “He did really well. It was probably the hardest class he had ever taken and the most work he ever had to do.”

Judon said that the AP class in high school is similar to what he faced in college at nearby Grand Valley State, where he led the nation in sacks last season, and what he now will experience as a fifth-round NFL draft pick of the Ravens.

The sixth of 10 siblings in a blended family, the 6-foot-3, 275-pound outside linebacker said Saturday that he is used to competition and loves to prove people wrong. Judon has carried a chip on his shoulder — maybe both of them — ever since being bypassed by most Division I schools.

“Always, you have to,” Judon said Saturday after his second rookie practice in Owings Mills. “I'm always willing to learn. When you stop trying to learn, you stop progressing. I don't care who didn't draft me or who didn't give me a scholarship. I care about the people I'm playing next to.”

Grand Valley State coach Matt Mitchell, who was the team's defensive coordinator when Judon was in high school, said his former star was 40 to 50 pounds lighter in high school and had not yet qualified academically when he was being recruited.

“I think that probably prevented anyone [on the Division I level] from pulling the trigger,” Mitchell said.

Judon said it turned out for the best.

“I'm glad I ended up at Grand Valley and I was blessed to be put in that situation,” he said. “I thought they had the best fit for me. They had some great coaches. They also had coaches that went to higher levels, so I felt the class of coaching I would get would be much better than if I chose to go at any other school at that level.”

Judon said the season-ending knee injury he suffered in the opening game of the 2013 season helped in his development. After getting a medical waiver from the NCAA last season, Judon won the Gene Upshaw Award as the top Division II lineman in the country.

“That was one of the best offseasons I've ever had,” Judon said of the months before the injury. “Unfortunately that knee injury happened. But then it prepared me. I became a student of the game. I became a coach on the sideline. ... All I did was take notes and watch film. Because of that, I knew the defense like the back of my hand.”

Said Mitchell: “To go through that adversity and kind of fight through the persistence and grit that it entailed turned him into a complete player. He's an elite pass rusher, I've never coached a guy who can rush the quarterback like he can.”

Judon finished last season with 21 sacks — one was added after the season was over — and his career with 35, a school record that knocked former Grand Valley State star Dan Skuta, now with the Jacksonville Jaguars, down a notch.

“I wouldn't say those numbers don't happen [in the NFL] because it did two years ago,” Judon said of the 22 sacks Kansas City Chiefs linebacker Justin Houston had in 2014. “I just feel like if I prepare and keep my body right and stay healthy, I have a chance to be a great player in this league. But I have to understand the game and I have to go through my rookie stage. I've got to learn the playbook first and foremost.”

Mitchell said he believes Judon has the chance to make an impact for a team that features two aging stars in Terrell Suggs and Elvis Dumervil, and drafted two other pass rushers in second-round pick Kamalei Correa of Boise State and third-round choice Bronson Kaufusi of Brigham Young.

“From a talent perspective and from the intangibles more than the talent, he's as good as any player since I've been here,” Mitchell said. “He's got a great takeoff, and a great motor, he's very unique in that way.”

The Ravens, who already have two former Division II players on the roster in defensive tackle Brandon Williams (Missouri-Southern State) and offensive lineman Ryan Jensen (Colorado State-Pueblo), have had Judon on their radar since last fall and saw him at the NFL scouting combine in February.

“That's the great thing about the combine is you get a chance to see guys from all different conferences and backgrounds and levels of football competing on the same stage,” assistant general manager Eric DeCosta said. “He had all the skills you look for — the athletic ability, the size and he had the production on tape, the ability on tape. His numbers were good.”