ORCHARD PARK, N.Y. (AP) — The Bills restocked their injury-depleted defense on Wednesday, elevating linebacker A.J. Klein from the practice squad and starting the process for linebacker Baylon Spector’s return, while placing All-Pro linebacker Matt Milano and starting nose tackle DaQuan Jones on injured reserve.

Cornerback Dane Jackson (foot) was added to the growing injury list on defense. Jackson was the only player on the active roster who did not participate in Wednesday’s practice. Rookie tight end Dalton Kincaid took part in the walk-through session, but has not yet cleared the NFL’s concussion protocol. Tight end Dawson Knox (wrist) and defensive end Greg Rousseau (foot) were limited on Wednesday.

The Bills (3-2) host the New York Giants (1-4) on Sunday night.

Milano hurt his lower right leg and Jones tore his pectoral muscle in a 25-20 loss to Jacksonville last weekend. Both require surgery and are out indefinitely. Bills coach Sean McDermott said he doesn’t believe “the door has been shut totally” either being able to return before the end of the season.

“A piece of it is playing for those guys too, because they were a big piece of this team and still are but they can’t help it so much now so we play for them,” McDermott said.

Buffalo was down five starters on defense against the Jaguars, with cornerback Tre’Davious White out for the remainder of the season after tearing his right Achilles tendon 10 days ago, and cornerback Christian Benford dealing with a shoulder injury. The Bills addressed their secondary on Tuesday by signing veteran cornerback Josh Norman to their practice squad.

“You never replace a player and I don’t like to get into comparing players,” McDermott said. “I don’t think that’s healthy. Overall, it’s the job of the person who is stepping in to do the job. And we have full confidence in that player, whoever that player is in this case.”

Klein is a 10-year veteran who was signed off Buffalo’s practice squad. The 32-year-old is familiar with the defense after spending much of the past three seasons in Buffalo, including closing last year with the Bills before being among the team’s final cuts in August.

Spector was designated to return after spending the first five weeks of the season on injured reserve after hurting his hamstring in August. The move opens a three-week window for Spector to practice before the team must determine whether to activate him. Buffalo filled Klein’s spot on the practice squad by signing defensive tackle Andrew Brown, who has four seasons of NFL experience and appeared in five games with Chicago last year.

The Associated Press contributed reporting.