While the team is in wait-and-see mode with Joseph, fellow safety Brian Branch is in his third month of rehab following a torn Achilles he suffered in early December.
"Look, they're both doing everything they can to get as healthy as possible," Lions general manager Brad Holmes said this week. "We haven't put a hard timeline or deadline, but we've been in regular communication with our medical staff, our medical staff's been in regular communication with the player, obviously, working with them.
"So, I know that they're on track to get as healthy as possible, but I think in like another month or so, then we'll obviously know a lot more."
The new league year and the start of free agency begins in less than two weeks, but Detroit should have a clearer picture of both players' progression and potential timeline for return by April's NFL Draft.