What Tatum Bethune’s Injury Means for the 49ers Defense in the Playoffs

The San Francisco 49ers’ linebacker group took another significant blow heading into the postseason, as head coach Kyle Shanahan confirmed that Tatum Bethune will miss the playoffs after suffering a serious groin injury in Week 18 against the Seattle Seahawks. Shanahan acknowledged that Bethune could require surgery, officially ending what had become a breakout season for the young linebacker.

Bethune exited the season finale late and did not return, losing Bethune removes a stabilizing presence from the middle of the unit just as the playoffs begin.

Bethune emerged as one of the most consistent defenders on the roster this season, stepping into a larger role as injuries mounted throughout the year. He finished the regular season as one of the team’s most productive linebackers, contributing across all three phases of defense. Losing him now is not just about numbers, it’s about losing a player who had earned the trust of the coaching staff in high-leverage situations.

With Bethune sidelined, Eric Kendricks will take over as the starting MIKE linebacker, and Shanahan made it clear the coaching staff is confident in the veteran’s ability to anchor the defense.

Kendricks played extensively in Week 18 and was arguably one of the 49ers’ best defensive players in the loss to Seattle. His experience showed, particularly in run fits, communication, and pre-snap alignments.

While Kendricks may not offer the same burst Bethune brought, his football IQ and reliability allow the 49ers to maintain structure in the middle of the defense. Much like Bethune never needed to be Fred Warner, Kendricks does not need to be Bethune, he just needs to be the best version of himself. 

Bethune’s injury is compounded by additional uncertainty at linebacker. Dee Winters is dealing with an ankle injury after appearing to have his calf stepped on in Week 18, while Luke Gifford is being evaluated for a quad injury. If Winters is unable to go, Garrett Wallow or Curtis Robinson would step in at WILL linebacker. Should Gifford miss time, that same duo would rotate at SAM.

The good news? The 49ers at least have a clear plan, with Kendricks now leading the group and younger linebackers filling defined roles around him.

There is cautious optimism surrounding Fred Warner, though his return would not come immediately. The 49ers are eyeing a potential NFC Championship Game return if they advance that far, at which point Warner’s practice window would be opened.

Until then, the defense will rely on Kendricks’ leadership and adaptability to hold things together in the middle.

Bethune’s injury is undeniably a setback, but it also highlights the importance of having a veteran like Kendricks on the roster. The 49ers have survived adversity all season. Now, with Bethune sidelined, their postseason hopes hinge on whether Kendricks and the reshuffled linebacker unit can rise to the moment and keep the defense playing at a championship contender level.