The Bears will be missing two of their five main defensive backs Sunday when they visit the Vikings in Minnesota.

Nickel back Buster Skrine remains in concussion protocol and will sit out his second straight game, while rookie cornerback Jaylon Johnson did not practice all week due to a shoulder injury and will not play after being downgraded from questionable to out on Saturday.

In last Sunday's win over the Texans, Duke Shelley replaced Skrine and Kindle Vildor entered in the third quarter after Johnson was injured.

"I have a lot of faith in them just because they're young guys that could get an opportunity, and you saw last week when forced into action, I thought they did well," said coach Matt Nagy.

Shelley, a 2019 sixth-round pick from Kansas State, had played just 14 defensive snaps in two seasons with the Bears before lining up for 53 against the Texans, recording three tackles and one pass breakup.

"I like his confidence," Nagy said. "He's a smaller-size guy, but he doesn't play that way. He's physical. He has really good ball skills. I was really impressed with how he played last week, and this week's he's going to definitely have a challenge as well. So he's in a good spot."

Vildor, a rookie fifth-round pick from Georgia Southern, had played just one defensive snap in the first 12 games this year before lining up for 14 versus Houston, registering two tackles.

"Just going back and watching his tape in college, you can see what type of playmaker he is and the way he can cover in man," Nagy said. "He has zone skills as well and he has a really good attitude.

"It's been fun while Jaylon's been out this week just watching in practice and in meetings Kyle Fuller being able to work with [Vildor] and just talk and help him out, and how receptive Kindle's been to that."

Safety Deon Bush (foot) has also been downgraded from questionable to out for Sunday's contest. Three other Bears played remain listed as questionable: outside linebacker Khalil Mack (shoulder), tight end Jimmy Graham (hip) and linebacker James Vaughters (knee), all of whom were limited in practice Friday.

Throughout the season, Mack has been limited in practice and listed as questionable with shoulder, knee, ankle and back injuries. But he has not missed a game.

Meanwhile, two of Minnesota's best players have been ruled out of Sunday's game due to injuries: tight end Kyle Rudolph (foot) and linebacker Eric Kendricks (calf). Running back Alexander Mattison (illness) is questionable.