Having already placed right tackle Donald Penn on injured reserve this week, the Raiders could be without another Pro Bowl offensive lineman against the Chargers on Sunday.

Left guard Kelechi Osemele did not practice all week due to a knee injury sustained in last weekend’s win over the Browns. He is listed as questionable for Sunday.

“It’s still very questionable,” head coach Jon Gruden said Friday. “We’ll have to wait and see.”

Osemele will travel with the team to Los Angeles, Gruden said. If he cannot play, Jon Feliciano, who replaced Osemele for eight snaps against the Browns, will likely start in his stead.

Feliciano is listed as the Raiders’ primary backup at both guard spots and center. He started at right guard in Week 5 of last season when Gabe Jackson was sidelined because of a foot injury and also played most of the Raiders’ Week 12 win over Denver after Jackson was ejected.

“It’s nothing new,” Feliciano said of playing as a backup. “I believe that I’m just as good as K.O. I know that’s saying a lot. But if you don’t believe it, then who else will, you know?”

Osemele, a Pro Bowl selection in 2016 and 2017, has missed just one game with the Raiders (Week 14 of 2016 with a kidney stone). Feliciano, who played mostly left guard in college, said he believes the two share an aggressive streak on the field.

“We both try to get after people,” Feliciano said. “After my rookie year, getting to know K.O, we were the same person, kind of, in that regard.”

The Raiders’ offensive line, a highly compensated and constant unit over the last few seasons, could look notably different Sunday. They are expected to start rookies at both tackle spots, with third-round pick Brandon Parker replacing Penn at right tackle and Kolton Miller on the left side.

Should Feliciano also start, center Rodney Hudson said the Raiders will have “a lot of confidence.”

“He’s played before, he knows what it takes,” Hudson said. “He plays hard. And he’ll be fine.”

Home away: The Raiders, as is customary before road games, pumped in artificial crowd noise during practices this week.

The host Chargers, apparently, did the same.

The Raiders have a strong Southern California fan base and had plenty of support when they visited the Chargers at the StubHub Center in Carson (Los Angeles County) last season. Gruden said the Raiders tried to prepare this week for any atmosphere.

“We had crowd noise all week on both sides of the ball,” Gruden said. “We expect this game to be that way no matter where it’s played. So we’ll be prepared for the noise. We’ve just got to be more prepared for the Chargers.”

Injury report: Safety Karl Joseph (hamstring) was ruled out for Sunday, meaning he’ll miss a second consecutive game. He and Osemele are the only Raiders players with injury designations for Sunday.

Matt Kawahara is a San Francisco Chronicle staff writer. Email: mkawahara@sfchronicle.com Twitter: @matthewkawahara