Here’s an excerpt from an article posted on espn.com by NFL analyst John Clayton:
"Do the Cardinals have the personnel to eventually switch to a 3-4 defense?New coach Ken Whisenhunt is pretty well set on offense with Matt Leinart at quarterback, Edgerrin James in the backfield and a great three-receiver set. Finding the personality of the defense is now the key. Former coach Dennis Green assembled an undersized 4-3. As we saw in San Francisco the past couple of years, it’s hard to make a quick conversion to a 3-4 because those schemes require bigger defenders to help stop the run. Chike Okeafor and Bertrand Berry have the athletic ability to be rush linebackers, but the team doesn’t have enough big linemen. Defensive tackle Alan Branch, the team’s second-round pick, will help the Cardinals get bigger. Expect the Cardinals to experiment with the 3-4 but stay a 4-3 on most of the early downs."
To be able to transition to the 3-4, the Cardinals need to get bigger and faster on the defensive side of the ball. As John Clayton mentions, Alan Branch helps with the size portion, and rookie LB Buster Davis should develop into a big playmaker in time, but I would also look for the Cards to stay in a 4-3 primarily in 2007 until the overall speed of that defensive unit improves.