The Dallas Cowboys’ defense took another late hit Sunday, ruling out starting linebacker Jack Sanborn with a groin injury just hours before their Week 8 showdown with the Denver Broncos at Mile High.

Sanborn’s absence piles onto a thin depth chart already missing three key defensive backs in Trevon Diggs (IR), Donovan Wilson, and top backup Juanyeh Thomas. Notably, Sanborn did not appear on the Cowboys’ injury reports Wednesday through Friday, making the day-of designation a surprise turn for a unit that’s been juggling personnel all week.

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Sanborn opened the season as Dallas’ starting middle linebacker for the first five games.

With him out, the Cowboys will lean further into rookie standout Shemar James, who has flashed downhill range and physicality and has led the team in tackles multiple times already this year. Expect rotational and sub-package tweaks to protect a short-handed back end, with more stress on the pass rush to keep Denver off schedule.

The timing is less than ideal. Denver has leaned on play-action and explosives to generate chunk gains, and the altitude typically magnifies snap-to-snap strain on coverage communication and linebacker fits. Dallas will need clean substitutions, tight leverage outside, and takeaway opportunism to offset the attrition.

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Kickoff is set for 3:25 p.m. CT on CBS, with Jim Nantz and former Cowboys QB Tony Romo on the call and Tracy Wolfson reporting from the sideline.

Another starter down, another next-man-up moment. If James’ emergence holds and the front four heats up early, Dallas can still dictate terms, even with a patched secondary and a reshuffled second level.