Starting safety Tracy Walker, who injured his right knee in the second half against the New York Giants, was ruled out against the Raiders. The team's other starting safety from two weeks ago, Quandre Diggs, is now in Seattle after being traded.
And the Lions are down to three safeties -- veteran Tavon Wilson, along with rookies C.J. Moore and Will Harris -- and a safety-turned-linebacker-turned-safety-again in Miles Killebrew, who is more known for his special teams work than what he's done defensively during his three-plus-year career.
"We're always ready to adjust based on whoever's out there," Lions coach Matt Patricia said. "Sometimes safety depth isn't necessarily from the safeties. In those situations, we do what we can to kind of overlap those situations if [Walker] can't play."
Another potential option in an emergency would be cornerback Mike Ford, who played some safety in the preseason. So there are options, but more emergency ones than anything else.
Walker has a team-high 56 tackles this season and has also defended five passes with an interception. Another of his main roles has been defending tight ends, which could be a problem for Detroit on Sunday when it faces Oakland's Darren Waller. Already a matchup problem for most of the league, Waller could now see a mix of players guarding him.
It could mean more of Wilson, among others, on tight ends.
"It'll be a group thing," Wilson said. "We'll take it on as a group and try to cover those guys as best we can. As a box safety I cover tight ends all the time. I'm always closer to the line of scrimmage. So I play some man coverage.
"You're always covering them. [Walker] ain't on them all the time."
In addition to the issues at safety, the Lions have questions at corner. Starter Darius Slay, who missed last week's game with a hamstring injury, is questionable but did more in practice this week than last and practiced in full on Friday. Rookie corner Amani Oruwariye is also questionable with a knee injury, leaving Detroit with six healthy corners.
Defensive tackle Mike Daniels (foot) is listed as doubtful and running back Tra Carson (hamstring), guard Graham Glasgow (back), defensive tackle A'Shawn Robinson (ankle) and defensive tackle Damon Harrison (groin) are questionable.