The Raiders young defense has shown some improvement in head coach Jack Del Rio's second season at the helm. Reuters

Though he may only miss a week, the potential loss of veteran cornerback Sean Smith further exposes a very green and an already vastly underachieving Oakland Raiders defense preparing for their biggest game of the season against the AFC West rival Denver Broncos Sunday.

Oakland’s first Week 9 injury report based off Wednesday’s practice also suggests the offensive line could be limited against Denver, while most of the Broncos' secondary was held out of their session.

Raiders center Rodney Hudson (knee), guard/tackle Kelechi Osemele (knee), tackle Donald Penn, and Smith were all held of practice, while guard/tackle Vadal Alexander (ankle) and tackle Menelik Watson (calf) were limited.

Defensive tackle Stacy McGee (ankle) also sat out Wednesday after missing all of last week with the same injury. McGee, who is second in sacks (2.5), was sidelined in last Sunday's win over the Tampa Bay Buccaneers.

Defensive end Mario Edwards Jr., who’s eligible to return from injured reserve this week after suffering a hip injury, did not return and could further limit a Raiders pass rush that’s totaled only 11.0 sacks this season.

The Broncos held back corners Chris Harris Jr. (not injury related) and Aqib Talib (back), along with safeties T.J. Ward (not injury related) and Darian Stewart (not injury related). Leading the team with three interceptions and 11 passes defensed, Talib missed Denver’s Week 8 victory over San Diego, his first absence all season.

Hudson, who has started all eight games this season, makes his first appearance on the injury report since Week 7 with the same knock. It’s Osemele’s first time on the report this season and he’s also started all eight games, while Penn has been listed before but has yet to miss a start for the NFL’s best pass protection unit. Oakland has allowed quarterback Derek Carr to be sacked only nine times this season, tops in the league.

A victory for either 6-2 team will break the logjam atop the division and likely places the winner next to the New England Patriots as the top teams in the AFC postseason race, but the Raiders will have to build on their strongest defensive effort of the season in order to overcome a youthful defense that reduces their chances of bumping off the defending champion Broncos.

Smith, now in his eighth year and by far the most seasoned cornerback on the roster, reportedly suffered an injury to his left shoulder early in Sunday’s 30-24 overtime victory over Tampa Bay and he’s “very questionable” to face Denver, ESPN reported Monday. He was limited to only two plays in Week 8, but Smith is still tied for the team lead with two interceptions and is second behind corner David Amerson with eight passes defensed this season.

The report said third-year corner T.J. Carrie is likely to fill Smith’s role in the starting lineup, but he’s one of the five cornerbacks presently on Oakland’s roster, excluding Smith, with four years or less experience. Antonio Hamilton is the sole rookie, while Amerson and D.J. Hayden are in their fourth years and Dexter McDonald his second.

And of that group, Amerson’s the only starter and Carrie’s recorded only three tackles, a forced fumble and one pass defensed over eight games. Last season, Carrie started 14 games last season for an Oakland secondary that finished No. 26 in yards allowed.

Much of the defense’s experience lies at safety and at linebacker, with leading tackler and 10-year vet Reggie Nelson, seventh-year safety Nate Allen, linebackers Riley Perry and Malcolm Smith (seven and six years of experience, respectively). Otherwise, six rookies round out the first two units of Oakland’s defensive rotation and first-round rookie Karl Joseph has been the sole producer with 31 tackles, one interception, five passes defended, and a fumble recovery.