The San Francisco 49ers did an excellent job keeping the Seattle Seahawks out of the endzone for nearly two-and-a-half quarters of their Week 11 clash.

But what had been a stout defensive performance reached a turning point with 9:26 to go in the third quarter when Nick Bosa sacked Geno Smith for a seven-yard loss that bizarrely ended up being arguably the most positive play of the game for the Seahawks. 

Bosa, limited in practice this week with a hip/oblique injury, injured his other hip on the play. Soon after, he left the game and did not return. With him reduced to the role of spectator, the Seahawks scored two touchdowns in pulling off a 20-17 upset win.

Seattle recovered from a sack that could have killed its second drive of the third period to score on a one-yard touchdown plunge from Kenneth Walker III at the end of an 11-play series.

Though the 49ers did get a key fourth-down stop in the fourth quarter to keep a 17-13 lead with under four minutes remaining, Bosa was left powerless watching from the sideline as, after the San Francisco offense failed to ice the game, Smith drove the Seahawks down for a game-winning score, taking it in himself on a 13-yard scamper.

It was a hugely frustrating experience for Bosa, who had 14 pressures in the 49ers' Week 6 win over Seattle and two sacks in this game, and he may have to play the role of spectator again in next week's clash with the Green Bay Packers.

Indeed, the 2022 Defensive Player of the Year, speaking after the loss dropped the Niners to 5-5 and last place in the NFC West, admitted to concern about his availability for a crucial rematch of last year's Divisional Round playoff clash.

"I guess I was compensating," Bosa said as he explained how the injury occurred. "I pushed through last week, and the same thing happened to my other oblique, so we'll see what I'm feeling like tomorrow."

Asked how it was watching on the sidelines, he replied: "Brutal. The most important time in the game for me to be out there and I wasn't able to be. I hate missing time, that's why I pushed through last week and hopefully it's not too long."

On his concern level about missing the Green Bay game, Bosa said: "It's definitely there. I don't know. I've got to see."

The 49ers can ill-afford too many more setbacks as their path towards a playoff berth continues to get narrower. 

San Francisco was able to pressure Smith consistently and got a positive performance from defensive Yetur Gross-Matos on his return from a knee injury. However, without Bosa, their defensive closer, the 49ers didn't have the horses to keep one of the game's better quarterbacks from willing the Seahawks to their first win over San Francisco since 2021. 

Right now, it's difficult to see them keeping Jordan Love and the Packers under wraps if Bosa is unable to play at Lambeau Field next week.

49ers become first team in nearly a quarter of a century to achieve unwanted feat that sums up their season

Another infuriating loss.