49ers-Raiders Preseason Preview: Depth battles heat up with concussion-related roster opening

The San Francisco 49ers will face the Las Vegas Raiders today, and the storyline for the week is less about headline stars and more about what happens when the defensive depth chart gets tested in the middle of a preseason routine. Yahoo Sports’ daily preview framed the matchup as an opportunity for several “under-the-radar” players to establish themselves, particularly on early downs where nickel-and-sub packages often decide who gets the most snaps.

A key roster thread involves defensive back CJ West. According to Yahoo Sports, the 49ers “played it safe” with West in one earlier exhibition, with him sitting out the first game of that span. Yahoo Sports then reported that West suffered a concussion in a practice last week, before returning on Sunday. While West is back, the report emphasizes that the interruption in routine preparation created space for other players to push their cases.

That space, in turn, has been described as an opening for undrafted rookies such as James Thompson Jr. or Bryson Eason. In preseason, those are the types of scenarios that can change who earns practice repetitions and who gets looked at for the next defensive package, because coaches can compare how younger players respond when the depth chart is temporarily altered.

The preview also points to the 49ers’ defensive development from a structural standpoint. The report notes that San Francisco will likely spend significant time in nickel defense, which tends to increase the importance of playmaking from the secondary and the ability to match up against the run and short passing games.

In that context, Yahoo Sports singled out Derrick Dugger and argued that his physical combination could translate to early and frequent field time. The preview described Dugger as 6-foot-5 with a 7-foot wingspan, and it referenced elite speed for his size with a 4.6-second 40-yard dash. The claim, as presented, was centered on how his traits may affect nickel usage and whether he can emerge as a consistent presence rather than a situational option.

Taken together, the matchup becomes a stress test for San Francisco’s young defense as it tries to “take a step forward,” with preseason reps serving as the measuring stick. Even with West back in the mix, the report’s emphasis on the concussion opening suggests the 49ers could still be evaluating whether the players who filled in during that window have earned continued involvement.

For what to watch next, the most practical indicators are snap distribution and package alignment: whether San Francisco leans on nickel more heavily than in the first exhibition, whether Dugger is integrated into early-down looks, and whether Thompson Jr. or Eason continues to get meaningful repetitions after West’s return. Those choices can reveal what the staff values most as it closes in on the regular-season roster decisions.

If West’s return is fully smooth, San Francisco may settle back into its preferred depth roles. If not, the same preseason pathways that Yahoo Sports described will matter again, because the 49ers’ ability to absorb disruptions can be as important as their ceiling when the regular season begins.