For Raiders’ Amerson, maturity rewarded

Recommended Video:

The popular theory about David Amerson is that Washington blew it by waiving the cornerback last year, and that the Raiders used him in the right scheme, allowing him to blossom.

Amerson himself will tell you that’s not true, and “it wasn’t rocket science” as to why the 2013 second-round pick flamed out in Washington.

“Once I got here, I matured,” Amerson said in a conference call Tuesday. “I came in the league and I was 21 years old. … I was taking that transition of becoming a professional (for granted) …

“Compared to when I was in Washington, instead of going home and playing video games all night and stuff like that, it was a much different approach.”

Amerson went home and watched game film and studied his playbook. And the hard work paid off, first with a starting job in Oakland, then a regular season with 29 broken-up passes, second most among cornerbacks in the NFL, and four interceptions.

And it paid off again Tuesday, when he signed a four-year contract extension worth up to $38.4 million.

With the Raiders, cornerback David Amerson broke up 29 passes — second most in the NFL among cornerbacks — and intercepted four passes. With the Raiders, cornerback David Amerson broke up 29 passes — second most in the NFL among cornerbacks — and intercepted four passes. Photo: Wesley Hitt, Getty Images Photo: Wesley Hitt, Getty Images Image 1 of / 7 Caption Close For Raiders’ Amerson, maturity rewarded 1 / 7 Back to Gallery

Amerson had a jump on opponents last year, like on the interception he returned for a touchdown against the Chiefs, because of something as simple as taking notes.

“Looking at my notes on whatever team we were playing that week…,” Amerson said. “It’s really just the little stuff. That’s what football is; it’s a game of inches. It just gave me that extra beat that I needed on Sunday to make plays out there.

“Like I said, it wasn’t rocket science. I knew what I had to do and it just clicked for me at a time where, like I said, I was being released and coming here. I’m kind of glad it happened like that.”

The Raiders took a cheap gamble on an athletic 6-foot-1 cornerback, and it paid off for them as well as for him. Amerson made plays on the ball not seen in these parts since the days of Pro Bowler Nnamdi Asomugha.

“By the grace of God, I was able to do it,” Amerson said. “It’s just a blessing that I have an organization that’s behind me and that supports me.…

“It was a perfect spot for me.”

Amerson clicked with the Raiders’ physical defensive scheme, and thanked head coach Jack Del Rio, defensive coordinator Ken Norton Jr., defensive backs coach Marcus Robertson and assistant defensive backs coach and Hall of Famer Rod Woodson for their help in bringing out Amerson’s best.

And yes, the scheme helped too.

“I think our scheme, especially last year, was more, ‘You know what we’re in, beat it’ type of stuff,” Amerson said. “So, it really made you go out there and play fast and just play football.”

Amerson was thrown into the fire the third game of the season.

“I barely knew the plays,” he said. “We’re breaking the huddle, I’m asking the guys, ‘What coverage is this? What do I got on this play?’ But, I was still able to go out there and compete and play fast football.”

Raiders general manager Reggie McKenzie spent up to $84.5 million, with $36.5 million guaranteed, on upgrading the secondary this offseason, signing free agent cornerback Sean Smith, safety Reggie Nelson and extending Amerson.

Expectations are high for a team that was 7-9 last season, and Amerson said it’s time to live up to them, starting next Wednesday at training camp in Napa.

“Guys have the mentality to work,” he said. “Once you know you put 100 percent effort into whatever your preparation is, you have to live with the results and let your talent and let your wings spread.”

Vic Tafur is a San Francisco Chronicle staff writer. Email: vtafur@sfchronicle.com Twitter: @VicTafur