The prize of the New Orleans Saints’ free-agent class has been placed on the shelf.

Coach Sean Payton on Friday announced safety Jairus Byrd underwent surgery to repair a torn lateral meniscus and was placed on season-ending injured reserve. The injury occurred on a noncontact play at Thursday’s practice as he turned to make a play on a ball.

Byrd’s procedure was performed by Dr. James Andrews. Payton described it as a “bucket-handle tear,” and said it will require more rehabilitation than a typical tear.

“I spoke to him for a while (Thursday),” Payton said. “One of the things I mentioned to him was the type of injury and he’s fully aware. It basically allows him to come back and be 100 percent.”

With Byrd out, safety Rafael Bush will move into the starting defense.

“It’s a big loss because he’s such a great person, but we have another player right behind him,” defensive coordinator Rob Ryan said.

Payton and Byrd’s teammates agreed that suffering such a noncontact injury at a practice instead of a game makes it more frustrating.

“To think of it happening to a guy like that — a freak play,” pass rusher Junior Galette said. “When you saw the play, no one thought it was that serious.”

This offseason, Byrd signed a six-year, $54 million contract, replacing Malcolm Jenkins, who signed with the Philadelphia Eagles and has three interceptions. The expectation was that Byrd, who created 33 turnovers during five seasons with the Buffalo Bills, would help the Saints improve in that category.

They’ve instead produced one turnover through four games — a forced fumble caused by Byrd in a Week 1 loss to the Atlanta Falcons — and rank 28th in pass defense with 272 yards allowed per game.

Byrd arrived in New Orleans with questions about his health. A foot injury sidelined him for six games last season, and this spring he underwent back surgery to repair a disc issue that was discovered after he signed with the Saints.

The operation sidelined Byrd for offseason workouts and he began training camp on the physically-unable-to-perform list. He was slowly brought along and missed the first two preseason games.

Once Byrd got healthy, the expectation was that he and Kenny Vaccaro would form one of the most imposing safety combinations in the NFL.

That hasn’t happened and the duo has come under fire in recent weeks after a slow start to the season, with most of the criticism based on the two missing a combined 16 tackles.

Bush, who has logged 91 of 277 snaps this season and has missed only one tackle, according to Pro Football Focus, has not historically faced such issues. Last season he logged 599 snaps, including playoffs, and missed one tackle. He finished 2013 with 42 tackles and one fumble recovery.

Bush said he is ready to step into a larger role.

“It changes some things we do scheme wise but it’s nothing we can’t get over,” Bush said.

“Me and Kenny (Vaccaro) play well together. He’s like my little brother.”

The lingering question, though, is if he and Vaccaro can get the defense to where it expects to be and if this changes the way the New Orleans defense operates.

The answers to those questions could determine the outcome of the season for a defense that was already struggling with their three-time Pro Bowler on the field.