Three weeks after Sean Payton announced his defense would have a new scheme in 2013 and nearly a week after he hired a coordinator to implement it, anxious New Orleans Saints fans have to be wondering what it’s all going to mean this fall.

So far, there has been little to go on.

But that’s not exactly surprising as new defensive coordinator Rob Ryan tries to settle in and begin the process of transitioning the Saints’ 4-3 base defense to a 3-4 front that Payton said he was switching to when he fired Steve Spagnuolo after just one season Jan. 24.

Inquisitive fans will have to be patient, though.

Rome wasn’t built in a day. Neither will the Saints’ new defense after it gave up an NFL record 7,042 yards in a 7-9 season, which cost Spagnuolo and secondary coach Ken Flajole their jobs.

The evaluation process will take some time before Ryan, Payton and General Manager Mickey Loomis figure out who’ll fit into the new scheme and, more importantly, how it’ll all come together in the coming months.

Loomis vowed last month that nothing would be swept under the rug, which means that every member of the defense is being scrutinized to see who will or won’t get a chance to return and be part of Ryan’s group.

Considering the Saints will have to shed some payroll to get under the salary cap, which is expected to be around $121 million, some hard decisions will have to be made before free agency begins March 12.

For example, do two aging and highly paid players — defensive end Will Smith and middle linebacker Jonathan Vilma — figure into their plans?

Once they make a decision on that, they must decide who will play nose tackle and who’ll line up as outside linebackers in the new 3-4.

Also, will the secondary get a major overhaul, with some new blood at cornerback and possibly at safety?

Payton did address one question this week when he told SiriusXM NFL Radio that Vilma, a prototypical 4-3 middle linebacker, could move outside in Ryan’s scheme.

Vilma didn’t like it when the New York Jets went to a 3-4 and he was traded to the Saints in 2008. But Payton said he believes Vilma can line up on the weak side, while Curtis Lofton, who played the middle last season, will be one of the anchors inside.

“The way that we’re going to run this defense and type of 3-4 we’re running will be such that you saw in Dallas or Houston,” Payton said.

That’s just a taste of what’s to come. There’s still much work to be done.

“You have the scouts who need to identify what the prototypes are for these positions different from what the scouts and everyone else in the building viewed as a prototype for the 4-3 scheme,” he said.

“Now, there are good football players that can fit into either one. But I think it allows everyone a chance to maybe visualize what we’re looking for.”