ENGLEWOOD, Colo. --A pair of rookies and a 15th-year veteran will be asked to step up in the absence of the team's starting middle linebacker on Sunday.

Head Coach John Fox announced on Thursday that Joe Mays' suspension was upheld, and he will miss Sunday's game against Houston.

The team's plan in replacing him in the center of the defense hasn't been completely mapped out yet. Keith Brooking has seen increased playing time through the first three games and got his first start of the year last week against Houston as a weakside linebacker. Against Oakland, he could move over and start in the middle.

"We're going to miss Joe, there's no doubt about that," Brooking said. "But we have a responsibility to go out there and fill that role the best we can."

In addition to Mays' absence, linebacker Nate Irving hasn't practiced yet this week after suffering a concussion against the Houston Texans. That could mean rookie linebackers Steven Johnson and Danny Trevathan will make their NFL debuts on defense this Sunday.

"They're ready," Defensive Coordinator Jack Del Rio said. "They need to be ready. They've been working on being ready. The closer you are to the action, the more that urgency picks up, and that has. That's been good."

Neither Trevathan, a sixth-round pick, nor Johnson, an undrafted free agent, has played a defensive snap in the regular season. Trevathan has been active for all three games, participating in more than 50 percent of the special teams plays this year, while Johnson was only active for the Atlanta game in which his role was also limited to special teams.

"I'm just trying to be as prepared as I can be," Johnson said. "I know my role is going to be bigger on special teams in the beginning, but if I do end up getting some time at Mike (middle linebacker), I look forward to going out there and doing the best I can do and helping my team to be able to stop their offense."

Johnson said his performance in the preseason, in which he led the team with 15 tackles, gives him some added confidence for Sunday. Still, the former Kansas Jayhawk knows the atmosphere at Sports Authority Field at Mile High will be different.

"It's just like preseason except it's turned up a little bit more," Johnson said. "Guys are bigger, stronger and faster. It's just football. It's basically just knowing what you have to do, knowing how to execute your job and understanding where you fit in the defense and you should be fine."

Even though Mays has taken nearly every snap at middle linebacker this year, he's not the only one who knows how to play the position. Each player in the linebacking corps is responsible to know how to play all of the different spots. That puts Brooking and crew in a better position to jump in Mays' place.

"The good thing with our linebacker positions is that we have to know everyone's job, everyone's responsibility," said Brooking, who has eight tackles and a forced fumble in 2012. "Guys at different positions are familiar being put in different roles. It's something that we just have to step up and fill that void the best we can."

For a five-time Pro Bowl linebacker in his 15th year in the league, any position feels like home.

"I've played Mike, Will, Sam, 3-4, 4-3, so I feel comfortable in those positions," Brooking said. "I feel like I have a grasp of this defense, so whatever role I play on Sunday, you better believe I'll be ready to go."

INJURY REPORT

For the Broncos, safety Quinton Carter (knee), linebacker Nate Irving (concussion) and wide receiver Matthew Willis (hamstring) did not participate in Thursday's practice. Guard Chris Kuper (forearm) was limited in the session, while running back Willis McGahee (ribs) jumped from limited in Wednesday's practice to full participation on Thursday. Cornerbacks Chris Harris (ankle) and Tracy Porter (knee) and tight end Jacob Tamme (groin) all participated fully in Thursday's session.

For the Raiders, tackle Khalif Barnes (groin), wide receiver Darrius Heyward-Bey (concussion/neck) and cornerback Shawntae Spencer (foot) did not participate in Thursday's practice. Defensive tackle Richard Seymour (knee), running back Mike Goodson (hamstring), kicker Sebastian Janikowski (left groin), nose tackle Tommy Kelly (knee), running back Darren McFadden (shoulder) and tight end Brandon Myers (concussion) were all limited. Center/guard Alex Parsons (shoulder), wide receiver Rod Streater (eye), tight end David Ausberry (shoulder) and defensive back Michael Huff (knee) fully participated in the Thursday session.