Two key Bears defensive starters did not practice Friday due to injuries and are listed as questionable for Sunday's home game against the Texans.

Linebacker Roquan Smith (hip) sat out for a third straight day with an injury he sustained in last Sunday night's loss to the Packers, while cornerback Jaylon Johnson (quad) was sidelined after being limited Thursday with an injury he suffered in practice.

Asked specifically about Smith's availability Sunday, coach Matt Eberflus said: "We'll have to see if he's going to be up or down. He's working towards the game and we're hopeful that he'll be there."

In other injury news, linebacker Matt Adams (hamstring), safety Dane Cruikshank (hamstring) and tight end Ryan Griffin (Achilles) have been ruled out of Sunday's game, while receiver Velus Jones Jr. (hamstring) is doubtful.

With Smith questionable and Adams out, the Bears could be thin at linebacker. The only other players on their 53-man roster at the position are veteran Nicholas Morrow undrafted rookies Jack Sanborn and Sterling Weatherford.

"We're looking at all combinations because if you were to have two guys down, obviously in pro football that's not good," Eberflus said. "We're working through that right now."

Sanborn is a Chicago area native who attended Lake Zurich High School and the University of Wisconsin. He impressed in the preseason, producing two takeaways with an interception and fumble recovery against the Chiefs and registering five tackles on defense and two on special teams in each of the first two games.

Eberflus is confident that Sanborn will be good to go if called upon Sunday.

"I think Sanborn is ready, I really do," Eberflus said. "I think he's excited to get going and if he gets his chance to play in the game in terms of playing linebacker, I think he's ready to do that. He's had a good week of practice too."

"I feel confident in myself," Sanborn added Friday. "And that's just from everything that we've gone through so far, all training camp and in practice and things like that. That's where your confidence has got to grow."

Jones, a rookie third-round pick from Tennessee, is expected to sit out his third straight game. 

"I stay patient because I'm a believer in everything happens for a reason," he said. "Just worry about the day ahead: 'What can I do to get better? What can I do to get myself back faster?' It's all about focusing on the day ahead and not trying to look too far down the line."

It appears that Jones is closer to returning, given that he practiced on a limited basis Thursday and Friday after sitting out Wednesday.

"It's a great feeling to be out there with your brothers," Jones said. "Just to be in the same atmosphere as them, grinding with them in individual [drills], it's an amazing feeling. I'm just fortunate and grateful to be here in the first place. Also to be back out there with them, that's definitely a changer. It makes me feel a whole lot better about myself."