Cornerback Chris Cook (hip) and safety Jamarca Sanford (groin) did not practice for a second consecutive days. Coach Leslie Frazier said he's hopeful that both players can do some work on Friday.
If not, there's a possiblility the Vikings could enter Sunday's game at Dallas without three starters in the secondary. Safety Harrison Smith already is on injured reserve because of turf toe.
"It's a little scary when you start getting into your depth this early in the season," Frazier said.
It's possible that the Vikings starting secondary on Sunday could consist of Andrew Sendejo and Mistral Raymond at safety and rookie Xavier Rhodes and Josh Robinson at cornerback with Marcus Sherels entering the game in nickel situations.
In other injury news, wide receiver Greg Jennings returned to practice after sitting out Wednesday because of a sore knee. Frazier said Jennings experienced some soreness while working out on his off-day this week. Jennings was limited on Thursday, but Frazier said the injury is not considered serious.
Running back Matt Asiata (personal) and tight end Rhett Ellison (ankle) did not practice.
Defensive tackle Fred Evans (knee) and right tackle Phil Loadholt (illness) were limited.