49ers' defense expects to be among NFL's elite

When the 49ers finished the 2008 season with a defense ranked 13th in the NFL, it represented a significant improvement from earlier in the year, as former coach Mike Nolan shuttled in players constantly and flip-flopped from a 3-4 front to a 4-3.

In replacing the fired Nolan just before midseason, Mike Singletary simplified the defensive approach and went with a straight 3-4 scheme. The results were tangible and players excelled.

That No. 13 ranking from last year is considered merely a starting point for 2009, as defensive coordinator Greg Manusky and his players believe they can be a top-10 defense, maybe even top five.

"Most definitely. No excuses this year," strong safety Michael Lewis said. "We've got the guys in place. We've got everything we need to be a successful defense and cause turnovers and get the ball back to the offense."