The San Francisco 49ers face a daunting task as they prepare to take on the Tennessee Titans this Sunday for their Week 15 matchup. The team will be without two key defensive starters, linebacker Tatum Bethune and defensive end Sam Okuayinonu, both sidelined by high-ankle sprains. This critical development forces the 49ers to adapt their defensive strategy significantly.

The absence of these starters comes at a crucial moment in the season, raising concerns about the team’s ability to contain the Titans’ offense. Levi’s Stadium will host this significant showdown, where the 49ers defense must rise to the occasion despite the setbacks. The Titans, on their end, also deal with their injuries but pose a formidable challenge with their powerful rushing attack.

Filling the void left by Bethune, Curtis Robinson is expected to step up in what’s set to be his third start this year. Additionally, the 49ers’ coaching staff will rely on a strategic rotation among their defensive linemen, including players like Bryce Huff and Keion White, who have previously demonstrated capability against high-caliber offenses NBC Sports Bay Area. As the clock ticks down to game day, all eyes will be tuned in to see how this reshuffled 49ers defense performs under heightened pressure.

49ers rule out two defensive starters for Sunday’s Week 15 game vs. Titans

The 49ers enter this matchup short-handed on defense because of several significant injuries and practice-window decisions. Coach Kyle Shanahan confirmed the inactivations, saying “Neither will be activated for the game,” as the team adjusts its depth chart. The moves force short-term lineup changes that affect both run defense and pass rush plans.

Key injuries and absences

• Tatum Bethune high-ankle sprain: Bethune was ruled out after aggravating a high-ankle sprain. He leads the team with 64 tackles this season, so his absence removes a primary tackler and play-caller from the linebacker corps.
• Sam Okuayinonu high-ankle sprain: Okuayinonu also suffered a high-ankle sprain and will not play. He started nine of 12 games and has two sacks. The team will need to replace his edge snaps and pass-rush reps.
• Nick Martin concussion protocol: Veteran center Nick Martin is listed out while he completes concussion protocol. His absence affects interior depth and special teams availability.
• Yetur Gross-Matos and Kurtis Rourke: Neither player was activated after their practice windows opened this week. As a result, the coaching staff must rely on rotation players to fill snaps.
• Eric Kendricks calf strain: Kendricks joined the team in late November but missed practice with a grade 1 calf strain. Shanahan noted, “If Kendricks were healthy, he would have been considered to start in place of Bethune.” Kendricks’ experience would have eased the linebacker transition.

Potential lineup changes

• Curtis Robinson is expected to start at linebacker in place of Bethune. Robinson will make his third career start on Sunday at Levi’s Stadium.
• The 49ers will rotate more defensive linemen, leaning on depth pieces such as Bryce Huff and Keion White. The staff used an eight-man rotation earlier this month.

Injury context and outlook

High-ankle sprains can sideline players for weeks, and they often hamper cutting and burst (see Mayo Clinic for details). Therefore, the 49ers will likely protect gimpy ankles with cautious snap counts. For team updates and official transactions, see the 49ers’ news feed. The Titans’ injury report provides context about opponent availability: see Titans news. As a result, San Francisco must adapt schematically while managing player workloads this week.

49ers rule out two defensive starters for Sunday’s Week 15 game vs. Titans

San Francisco’s defensive depth chart will look different on Sunday because of multiple absences. The losses of Tatum Bethune and Sam Okuayinonu weaken both run support and edge rush. Therefore, the 49ers must adjust rotations and play calls to protect vulnerable gaps.

Key player absences and impact

• 49ers
  • Tatum Bethune ruled out with a high-ankle sprain. He leads the team with 64 tackles, so his absence reduces middle-of-field tackling and linebacker leadership.
  • Sam Okuayinonu ruled out with a high-ankle sprain. He started nine games and has two sacks, so the team loses a starting pass-rush option.
  • Nick Martin out under concussion protocol, which affects interior depth and snap flexibility.
  • Yetur Gross-Matos and Kurtis Rourke not activated after practice windows opened, trimming the available pass-rush rotation.
  • Eric Kendricks limited by a grade 1 calf strain and did not practice. If healthy, he would have been a candidate to start.
• Titans
  • Jalyn Armour-Davis out with an Achilles injury and several players listed as questionable on the team report. This reduces Tennessee’s defensive secondary depth.

Rotation and strategy implications

Because the 49ers lack two starters, expect heavier use of depth players. Curtis Robinson will likely start at linebacker. Additionally, coaches will rotate more defensive linemen, as they did earlier this season with eight-man rotations that included Bryce Huff and Keion White. Consequently, San Francisco may play fewer exotic blitzes and instead focus on gap integrity and controlled pass rush. Opposing offenses can test those adjustments by attacking edges and short-yardage runs.

For injury context and official status updates, see the 49ers’ news feed at 49ers News and the Titans’ injury report at Titans News. For how high-ankle sprains affect performance, see this article.

Projected replacements vs. starters for Week 15

The table below compares ruled-out starters with likely replacements to highlight starter production and depth implications.

Data note: Stats current through team reports as of December 14, 2025. Dashes indicate unavailable or not publicly reported totals.

Key takeaways

• Bethune’s 64 tackles represent the single biggest production loss.
• Expect increased rotation snaps for Bryce Huff and Keion White; coaches will likely emphasize gap integrity and controlled pass rush.

San Francisco ruled out two defensive starters for Sunday’s Week 15 game vs. Titans.

The moves leave a clear hole in the 49ers’ front seven.

Linebacker Tatum Bethune and defensive end Sam Okuayinonu are out with high-ankle sprains.

Therefore, the team loses Bethune’s 64 tackles and a starting edge rusher with two sacks.

Nick Martin is in concussion protocol, and Yetur Gross-Matos plus Kurtis Rourke were not activated after practice windows.

Eric Kendricks missed practice with a grade 1 calf strain, so he was not available to replace Bethune.

As a result, the 49ers will turn to Curtis Robinson as the expected starter.

Additionally, rotation players such as Bryce Huff and Keion White will absorb extra snaps.

Strategically, coaches may emphasize gap integrity and controlled pass rush rather than aggressive blitzing.

Consequently, short-yardage runs and edge attacks could decide this game at Levi’s Stadium.

For more coverage, follow Rams News LLC at Rams News LLC and on Twitter at @ZachGatsby.

Frequently Asked Questions (FAQs)