Emmanuel Moseley's season is over, and the Detroit Lions are once again dealing with depth issues in their secondary.

Moseley, one of four key additions to the Lions' defensive backfield this offseason, tore the ACL in his right knee in his Lions debut Sunday against the Carolina Panthers, Lions coach Dan Campbell confirmed Monday.

Moseley was returning from a left ACL tear he suffered last October in a game against the Panthers while with the San Francisco 49ers. He did not play in the season's first four games after undergoing a clean-up procedure on his left knee this summer and pulling his hamstring in his return to practice in September.

"It’s unfortunate but we just got confirmation on that a little bit ago," Campbell said. "Hate it for him. And it’s frustrating to put all that work in and then this happens on the other one. But, just knowing him and knowing the way he works, this’ll sting for a little bit and then he’ll go back to work and then he’ll come back and be ready to go when the time is right."

Moseley was hurt on his second snap of Sunday's game, when his knee gave out while planting to chase a Panthers receiver in coverage.

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The Lions lost starting safety C.J. Gardner-Johnson, another one of their top free agent additions, to a torn pectoral muscle in Week 2. Gardner-Johnson underwent surgery in late September and could make a late-season return.

Cam Sutton, the Lions' third major defensive free agent addition from spring, and Jerry Jacobs, who has a team-high three interceptions through five games, have started all five games at cornerback this season, but Moseley's injury leaves the Lions without a proven backup.

Rookie defensive back Brian Branch missed Sunday's game with an ankle injury and his status for this week's game against the Tampa Bay Buccaneers is uncertain. Will Harris played in sub packages in Branch's place against the Panthers. Undrafted rookie Steven Gilmore did not play a defensive snap.

Harris could serve as the team's No. 3 outside cornerback once Branch returns.

"Will’s somebody we’ve got a lot of trust in," Campbell said last week. "He’s banked a lot of nickel reps. And there again, Will, not only to be able to play nickel, outside corner, safety in a pinch, he’s just got so much versatility for us. So that’s good."

Contact Dave Birkett at dbirkett@freepress.com. Follow him @davebirkett.

This article originally appeared on Detroit Free Press: Emmanuel Moseley's knee injury latest blow to Lions depleted secondary