The rare 11-1 team in a heated battle for a No. 1 seed, the Steelers will make their trip to Buffalo severely shorthanded at linebacker.

Pittsburgh placed Robert Spillane on IR Saturday. The recent replacement starter suffered a knee injury during the Steelers’ loss to Washington on Monday. He will join Devin Bush on the injured list, though it is not certain if Spillane is out for the season. The young defender will be out until at least Week 17, however.

Altogether, the Steelers are down Spillane, Bush and Vince Williams at off-ball linebacker. The latter is on the team’s reserve/COVID-19 list. This will increase the importance of the team’s October trade for Avery Williamson. The veteran stands to be a first-stringer against the Bills; his most recent start came in Week 8 when still a member of the Jets.

Spillane stepped in for Bush after he went down earlier in the season. A third-year UDFA, Spillane started seven games, made 45 tackles and returned an interception for a touchdown against the Ravens.

The Steelers made multiple moves to help with linebacker depth Saturday, activating Ulysees Gilbert and promoting Tegray Scales from their practice squad. Pittsburgh is tied with Kansas City atop the AFC, though the Steelers still hold the tiebreaker.