Detroit Lions cornerback Emmanuel Moseley suffered a torn pectoral muscle in practice this week and is out indefinitely, sources told ESPN's Adam Schefter.
Coach Dan Campbell confirmed Tuesday that Moseley is sidelined indefinitely but did not confirm the nature of the injury.
It marks the third consecutive season that Moseley has suffered a major injury.
After missing the final 12 games of the 2022 season because of a torn left ACL, Moseley appeared in only one game with the Lions last season because of a torn ACL in his right knee.
"It's tough," Campbell said Tuesday. "That's tough. He's the one that's put so much work coming back from two ACLs. It's frustrating, but he knows. Look, you've got two decisions, you either rally one more time, or you say, you know what, enough is enough. My gut is going to tell me he's going to rally again.
"Nothing says that he may not be ready by the end of the year. I mean we're still trying to figure all those things out."
Moseley was transitioning away from outside cornerback during training camp and competing with Amik Robertson and Ifeatu Melifonwu for Detroit's primary nickel cornerback spot.
Campbell on Tuesday also mentioned Ennis Rakestraw Jr. as a player who is taking reps at nickel.
Moseley, 28, has four interceptions and 162 tackles in 46 career games -- 33 starts -- with the Lions and San Francisco 49ers.