Vasher was a Chicago Bear for the first six seasons of his career before going to San Diego this offseason. He didn't make the team, however, becoming a free agent yet again. As mentioned, the Lions brought him in for a visit last week, and by signing him now, his salary isn't guaranteed for the season.
Right now it's unclear who will be moved to make room for Vasher, but Dave Birkett speculates that Aaron Berry could be headed to injured reserve.
The Lions have not announced Vasher's signing or a corresponding move on the 53-man roster, but nickel cornerback Aaron Berry suffered a shoulder injury in Sunday's season-opening loss to the Bears and is a candidate to go on injured reserve.
"Aaron Berry had a shoulder that reoccurred a couple times in the game," Lions coach Jim Schwartz said in his Monday press conference. "That’s something we’ll look hard at that also."
I certainly hope Berry's injury isn't of the season-ending variety, because he played well on Sunday, picking off a Jay Cutler pass. He was injured for much of training camp but made the roster anyways, so there's no doubt the talent is there. The question is if he can stay healthy or not.