Backup strong safety Willie Offord, who started in place of Darren Sharper in Sunday's 33-16 victory over New Orleans, suffered a torn anterior cruciate ligament in his left knee during the fourth quarter. An MRI on Monday morning revealed the extent of the injury, which will end his season.
Sharper, meanwhile, tested his sprained left knee by doing some running Monday, and didn't seem overly optimistic about the result.
Coach Mike Tice said Sharper likely will be listed as probable when the first injury report is issued Wednesday, but the veteran could elect to hold himself out for another week. That would give Sharper three weeks, including the Vikings' bye on Oct. 9, to rest the injury.
Sharper said Monday he will probably attempt to practice Thursday to test the knee.
If Sharper doesn't go, the Vikings will have to make a decision about who starts along with Corey Chavous at safety. Chavous moved from strong to free safety against the Saints, with Offord playing strong safety.
The Vikings could give the starting assignment to Ken Irvin, but there might be some concern about his experience at the position. Irvin, an 11-year veteran, had been used exclusively at cornerback during his career until training camp.
"Whatever situation I'm called upon to be in then that's fine, "said Irvin, who is expected to be at free safety with the first team for Wednesday's practice." We have a lot of depth on this team. I know every position in the back end, and that's the role I'm playing right now. I'm certainly capable of going in there and playing free safety."
It appears likely that first-year player Will Hunter will be promoted from the practice squad to help add some depth. A third option is for the Vikings to look outside the organization for help.
The loss of Offord also is a blow because he serves as the captain for the special teams. The Vikings have shown significant improvement in that area this season.
"He is an emotional leader on special teams," coach Mike Tice said. "He is tough, calls guys out, makes them meet on Fridays after practice when guys want to go home. He is in there meeting with them. The leadership that we are going to lose is significant. He is playing really well on special teams; that is significant. Not to (mention) the fact that he has played really well on defense. It is a big loss, big loss."