ORCHARD PARK, N.Y. (AP) — The Buffalo Bills placed linebacker Matt Milano and defensive tackle DaQuan Jones on injured reserve and signed linebacker A.J. Klein to their roster on Wednesday, continuing the process of reinforcing their injury-depleted defense.

In other moves, second-year linebacker Baylon Spector was designated to return after spending the first five weeks of the season on injured reserve after hurting his hamstring in August. The designation opens a three-week window for Spector to begin practicing 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.

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.

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. McDermott said “the door hasn’t been shut” on either being able to return before the end of the season.

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.

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.

WIVB digital sports reporter Jonah Bronstein contributed.