After it was revealed Thursday that Saints linebacker Jonathan Vilma would undergo arthroscopic knee surgery, forcing him to possibly sit out at least the rest of the preseason, coach Sean Payton downplayed worries about the player’s health and the depth at his position.

Payton told news media that the procedure Vilma was submitting himself to in Philadelphia differed from previous ones he’s had.

“He’s getting scoped,” Payton said. “We’ll have him back and kind of go from there.”

Meanwhile, Payton suggested he and his staff would make the most of the situation and take long looks at other inside linebackers on the roster, among them David Hawthorne and Ramon Humber.

“The most important thing is getting a chance to evaluate all of these players,” Payton said. “A guy like Jon Vilma — I know exactly what we have in that player. So it gives us a chance to see not only Hawthorne more; but, if he’s going earlier, than the guys behind him are getting to play quicker, too.”

Vilma had been in and out of training camp sessions since Aug. 5, and he missed the Aug. 9 preseason opener against the Kansas City Chiefs. Payton on Thursday then confirmed reports that a surgery would be performed to relieve discomfort and swelling Vilma had been experiencing in one of his knees.

Payton didn’t discuss when Vilma would return. But one of the reports said Vilma could be back for the first regular season game against the Atlanta Falcons at the Mercedes-Benz Superdome on Sept. 8.

Vilma, a projected starter at weakside inside linebacker, is but one of several Saints defenders to get hurt and miss practice as the team installs the 3-4 scheme Rob Ryan brought with him to New Orleans since being hired in February.

Martez Wilson hurt his elbow July 29 and returned to practice in a limited capacity Aug. 13. Junior Galette injured his left leg Aug. 7 and had not returned to practice as of Thursday.

Wilson and Galette are vying to replace Victor Butler, who at one point was expected to start at strongside outside linebacker but will miss the season after tearing an ACL during organized team activities in June.

Butler isn’t the only Saints defender slated to be out for the year following an injury. Kenyon Coleman, penciled in as a starter at left defensive end, tore a pectoral muscle on Aug. 6 and will miss the 2013 campaign as well.

With Vilma unavailable, Hawthorne has been lining up with the first-team defense. He’s had his good moments in training camp, such as when he intercepted second-team quarterbacks Luke McCown during the Aug. 3 Black and Gold scrimmage and Seneca Wallace in a drill on Monday during a simulated second-down play around the red zone.

Hawthorne had a combined three tackles in the 17-13 win against the Chiefs. Last year, Hawthorne, who came to the Saints after four seasons in Seattle, missed five games for New Orleans with an injured hamstring but finished with a combined total of 43 tackles, 20 of them solo.

“If I just go out there and do what I do, ... everything else will take care of itself,” Hawthorne said in reply to a reporter’s question about whether Vilma’s setback represented a chance to audition for a starting job. “I’ve got 100 percent confidence in myself and everything I do.”

For his part, Humber appeared in 13 games for the Saints in 2012, mostly on special teams. He had 14 coverage stops, tied for second most on the team.

Humber has been backing up strongside inside linebacker Curtis Lofton, who sat out Thursday afternoon’s practice for undisclosed reasons after missing a couple of sessions the first week of training camp with a sore back.

Humber claimed to “definitely feel comfortable” at either inside linebacker position.

“As a linebacker, you have to learn the whole defensive system,” Humber said. “You’re pretty much the quarterback of the defense, so you have to know all the moving parts.”

Other inside linebackers for the Saints are seventh-year pro Will Herring and Chris Chamberlain, a sixth-year man who’s been dealing with an undisclosed injury.

Knee injuries have been a recurring issue for Vilma, 31.

The New York Jets traded Vilma to the Saints after he had a season-ending knee injury in 2007, when he played seven games. He spent the first six weeks of last year on the physically unable to perform list as he recovered from offseason surgery on his left knee, and he missed a total of five games with knee problems in 2011.

While appealing a season-long suspension given to him in the wake of the bounty scandal, a punishment that was ultimately vacated, Vilma started 10 games for the Saints, getting a combined 49 tackles, 21 of them solo. He also had an interception, from which he scored a touchdown on an 18-yard return.

Speculation about whether Vilma’s career was doomed because of the matter with his knee spread on the web and the airwaves Thursday, but Humber insisted his teammate would be back in short order.

“I know (Vilma), and he’s a fighter,” Humber said. “I know he’ll be ready to go whenever he comes back, and it’s probably going to be sooner than later.”