Hanson had been released last week by Philadelphia after spending six seasons as the Eagles' nickel cornerback, where he excelled playing in the slot.
"He's been a guy that's played a lot of years in the league in the slot and we just felt like it was a good thing to get another veteran guy in there with what really amounts to a young room. And so we thought that was something that helped us and upgraded our team and made us better," coach Dennis Allen said.
The move to get rid of Van Dyke means all six cornerbacks on the Oakland roster are new to the organization. Oakland released starters Stanford Routt and Chris Johnson before the start of free agency, let Lito Sheppard leave as a free agent, and released both cornerbacks taken in the 2011 draft. The team is transitioning from the bump-and-run style preferred by former owner Al Davis to Allen's new defense that will feature more zone coverage.
The Raiders waived fourth-round pick Chimdi Chekwa on Friday before bringing him back to the practice squad, then cut ties with Van Dyke on Monday.
Free-agent acquisitions Ron Bartell and Shawntae Spencer are slated as the starters, with Hanson expecting to get time in nickel packages. Pat Lee, Phillip Adams and Coye Francies round out the cornerback group, with Adams and Francies being added in the past week.
"As things played out throughout OTAs, minicamp and in training camp, we felt like that was a position that we needed to try to upgrade and we felt like with the players that we brought in here that it helps us as a team to be better," Allen said.
Hanson spent one season as an undrafted free agent with San Francisco before joining the Eagles in 2006. He has played 104 games with 19 starts and four interceptions. He played mostly in the slot for the Eagles and allowed 21 catches on 42 attempts for 232 yards and two touchdowns, according to game-tracking numbers compiled by STATS LLC.
Over the last four seasons, Hanson has allowed opponents to complete 54.5 percent of their passes for an average of 5.3 yards per attempt and a 76.5 passer rating against.
"It's mostly his intelligence," Allen said. "He's really smart. He's got good quickness inside and so he matches up with some of the smaller, quicker slot receivers. I just think he just understands route combinations and how things happen inside in the slot, and I think that's the biggest learning adjustment that anybody that goes in and plays the nickel position."
Allen said Hanson seemed to grasp the defense quickly in his meetings with the coaching staff and could be able to contribute in the opener next Monday against San Diego.
"I feel like in the next couple of days I'll get it down," Hanson said. "I went over the whole playbook already, so it's just now about all about studying and reiterating it to myself. It's the same defense, a 4-3 defense, it's just different names, different plays, but once I get that down I'll be ready to go."
Van Dyke was a prototypical Al Davis player, having run the fastest 40-yard dash time at the NFL combine in 2011 at 4.28 seconds. That contributed to the Raiders taking him in the third round despite the fact Van Dyke started just three games his senior season at Miami.
Van Dyke had difficulty in his first preseason and saw limited action as a rookie. He started just four games but showed promise as he allowed opponents to complete just 14 of 32 passes for 167 yards with one touchdown allowed and one interception, according to STATS LLC.
He got off to a fast start in training camp but struggled in exhibition games and was ultimately let go in favor of the more seasoned Hanson.
"Just want to thank Al Davis and the Raiders organization for giving me a opportunity to play in the NFL!" Van Dyke wrote on his Twitter account.
In all, the Raiders have 23 players on their 53-man roster who were not with the organization last season, including the six new cornerbacks, five new offensive linemen and four new linebackers.
