Bears rookie receiver Velus Jones Jr. (hamstring) did not practice Friday for the third straight day and is listed as doubtful for Sunday's season opener against the 49ers.

Coach Matt Eberflus confirmed that the hamstring injury is the same issue that sidelined the third-round pick at various times throughout training camp and the preseason.

"He's working through that," Eberflus said. "We're close. We're getting close with it. I think it's going to be good here soon."

Another member of this year's draft class, fifth-round defensive end Dominique Robinson (knee), was a full participant in Friday's practice after being limited Wednesday and Thursday and is questionable.

If Robinson is active, he'll be part of a defensive line rotation that defensive coordinator Alan Williams likened to line changes in hockey "where guys go in and then they come out and the next group goes in."

"We'll have a lot of D-linemen up and we'll be ready to go," Williams said. "Everyone should be participating, everyone should be contributing."

From the first day of the offseason program, the Bears have planned on making frequent substitutions to keep their defensive linemen fresh.

"We told guys this is going to be the hardest thing you're ever going to do from a sports standpoint, so we've been preparing for this since Day 1," Williams said. "What we do is we run all day long, and so our guys are prepared to get out there and go, to exhaust everything they have, to put it out there on the field and then they'll get a blow and the next group will come in. And then they'll do the same thing and the next group will come in after that."

Offensive lineman Lucas Patrick returned to practice Monday for the first time since injuring his right hand in the second training camp workout July 28. He practiced all week without restrictions and is not on the injury report.

Eberflus conceded that he knows where Patrick will play Sunday, but the Bears coach declined to share that information because it would help the 49ers create favorable matchups. A regular starter for the Packers the past two seasons, Patrick opened games at both center and guard.

"I've been a defensive coach a long time," Eberflus said. "Why would I reveal anything right now that I don't need to? We'll see where he's at and we'll see where he's going to play, and that's where it is right now."

For the 49ers, star tight end George Kittle (groin) did not practice Friday for the third straight day and is questionable for Sunday's game. 

A three-time Pro Bowler in five seasons with the 49ers, Kittle is an integral part of San Francisco's offense. Last year he started all 14 games he played, catching 71 passes for 910 yards and six touchdowns. 

If Kittle is unable to play, the 49ers likely will lean on standout receiver Deebo Samuel, wideout Brandon Aiyuk, running back Elijah Mitchell and fullback Kyle Juszczyk to help pick up the slack. 

"They're good, solid players," Eberflus said. "Obviously, no one is George Kittle. Kittle is Kittle. He is a special human and he's got a dynamic play to him in terms of his effort, his attitude, his blocking, his run after the catch. But the other guys, they'll fill in and do a good job. [Juszczyk] is there. [He] can do a lot of things for them. He's a spot player, [they] put him all over the place."

Roster moves: In other news Friday, the Bears terminated the contracts of veteran defensive tackle Mike Pennel Jr. from their 53-man roster and defensive end Sam Kamara from their practice squad.