Lions head coach Dan Campbell said Friday that Joseph (knee) is a possible injured reserve candidate, Tim Twentyman of the Lions' official site reports.
Joseph appeared as a limited participant in practice Wednesday but appeared to have suffered a setback after no participation Thursday or Friday. It looks as though the 25-year-old is set to miss an extended period of time, and it's currently unknown when he will return this season. Thomas Harper will remain as a starting safety in Kerby's absence.