Bears center Cody Whitehair on Friday was ruled out of Sunday's home game against the Saints with a calf injury he sustained in last Monday night's road loss to the Rams.

Whitehair, who was unable to practice all week, has started all 71 games since joining the Bears in 2016 as a second-round draft pick from Kansas State. Beginning in 2018, the 6-3, 313-pounder had not missed a single play in 39 games before exiting late in the third quarter versus the Rams.

After replacing Whitehair in Los Angeles, first-year pro Sam Mustipher is expected to make his first NFL start Sunday against the Saints. Mustipher signed with the Bears last year as an undrafted free agent from Notre Dame and spent his entire rookie season on the practice squad. The 6-2, 314-pounder remained on the practice squad for the first five weeks this season before being promoted to the active roster Oct. 14 after left guard James Daniels suffered a season-ending chest injury.

At Notre Dame, Mustipher started all 37 games over his final three seasons at center and graduated with a computer science degree. 

The Bears are confident in Mustipher's ability to step in and handle all of the responsibilities that come with playing center in the NFL.

"The biggest thing probably is the communication with these centers in regards to the 'Mike' [linebacker] ID calls and the different looks you can get," said coach Matt Nagy. "The one thing I would say with a guy like Sam Mustipher is here's a guy that takes the game extremely seriously. He's been playing center for a long time. He's a natural born leader. You can feel it. Super hard worker.

"Are there times where things could happen, as in last week where you might get beat technique-wise here or there? Yeah. But it sure as heck isn't going to be because of effort and want. And so you take that, you combine that with his teammates on that line and you combine that with [offensive line coach] Juan Castillo and [assistant] Donny [Raiola], you just do nothing but just keep plugging away. I thought that Sam has had a really good week of practice, and now we'll see where it goes."

In other injury news, receiver Allen Robinson II remains in the NFL's concussion protocol and is listed as doubtful after sitting out practice all week. It remains uncertain whether Robinson, who suffered a concussion late in the loss to the Rams, will be able to play against the Saints.

"I've got to see how that goes with that whole protocol and what they say he can and can't do," Nagy said. "If he's able to pass through it and everything is good to go, of course we want him to be out there. I think that's probably the best answer for me to give you considering the protocol. It's kind of out of our hands."

Robinson leads the Bears in receiving with 44 catches for 544 yards and two touchdowns. The seventh-year pro has appeared in 36 of 39 games since signing with the Bears in 2018, missing two contests with a groin injury and one with a rib injury in 2018.

Four other Bears players are questionable for Sunday's game: Safeties Eddie Jackson (knee) and Sherrick McManis (hamstring) both practiced without restrictions Friday, while outside linebacker Khalil Mack (ankle) and wide receiver/return specialist Cordarrelle Patterson (quad) were limited.

The Saints, meanwhile, have ruled three players out of the contest, including star receiver Michael Thomas (ankle/hamstring). The others are receiver Marquez Callaway (ankle) and guard Nick Easton (concussion).