The Bears on Friday ruled star outside linebacker Khalil Mack out of Sunday's home game against the 49ers.

The six-time Pro Bowler has been hampered by a foot injury he sustained Sept. 26 against the Browns. Since suffering the injury, Mack has been either limited or held completely out of practice but has not missed a game. He did not practice in any capacity this week.

Mack has not allowed the injury to slow him down. He recorded one sack in each of the two games that followed the Lions contest and leads the Bears with 6.0 sacks. His 6.0 sacks are the most he's recorded through the first six games in his eight NFL seasons.

"He's a great leader," said coach Matt Nagy. "I mean, for what he does on the field, this has been one of the fastest starts he's had in his career production-wide. You feel it. You see it. He's had a couple weeks there where he's not been able to practice, but he's been able to strap it up on Sunday and get out there and do a lot of great things. 

"The want is there, but we've got to sometimes protect Khalil from himself, and that's kind of where we're at right now and continue to work through things with him, open communication and come up with a good plan as to what it is as we move forward."

The Bears have not yet determined whether they will place Mack on injured reserve, which would require him to sit out at least three games. 

"We have not made any decisions," Nagy said. "Keeping Khalil out for this weekend, he obviously would love to be able to go, but that's where we're at with him. We'll continue to just work through that situation with him.

"He's trying to continue to keep playing and we've got to work together and say, 'OK, well, is it going to get any better or is it not?' And that's kind of where we're at right now. So, he's playing through the pain and he's being productive and all that. You also, after every game, you've got to reevaluate. He's got to tell us, 'OK, how do you feel?' And then we've got to look medically and see, 'OK, where are you at?' Put the two together and say, 'What's the plan moving forward?' That's where we're at right now."

Mack has played in 117 of a possible 119 games since being selected by the Raiders with the fifth pick in the first round of the 2014 draft. He started all 64 contests in four seasons with the Raiders and has been nearly as durable with the Bears, playing in 53 of a possible 55 games since he was acquired in a blockbuster trade in 2018.

Mack has started 47 straight games for the Bears after sitting out back-to-back contests midway through the 2018 season due to an ankle injury. 

Mack's absence will be mitigated a bit by the expected return of outside linebacker Robert Quinn, who was activated off the COVID-19 list Friday. Quinn, who missed last Sunday's game in Tampa, is second on the Bears behind Mack with 5.5 sacks.

"[Mack is] such a dynamic player," said veteran defensive tackle Akiem Hicks, "somebody that's able to play all over the field, somebody that does such a great job in any position that you put him in. It's a spark that we have on our team that's most necessary. But if we don't have that spark, we have to ask for another one to step in and play to the best of their ability."

In other injury news, five Bears players are listed as questionable for Sunday's game: Safety Tashaun Gipson Sr. (hip) was limited in practice Friday, while Hicks (groin), tight end Jesper Horsted (knee), linebacker Sam Kamara (knee) and return specialist Jakeem Grant Sr. (ankle) were all full participants.