Nick Bosa Out vs Seahawks, Eyes Week 6 Return

Nick Bosa will not play Sunday in Seattle. The 49ers ruled their star pass rusher out for the Week 5 showdown with the Seahawks, his third straight missed game, but Bosa told NBC Sports Bay Area on Friday that it is "pretty darn likely" he is back for the Monday, Oct. 19 home game against the Washington Commanders.

That matters, because this is the biggest game of the young season in the NFC West. San Francisco is 4-0, Seattle is 3-1, and the Niners are walking into Lumen Field without the guy who usually wrecks these games. Bosa is not even traveling with the team this weekend.

How the calf injury happened

Bosa hurt his left calf during his pre-practice warmup routine on Thursday, Sept. 24, per NBC Sports Bay Area. The final injury report lists him with knee and calf issues, and he did not practice this week.

It has been a rough run for him. He missed most of last season with a torn ACL in his right knee, so a new soft-tissue injury on the other leg was not what anybody in Santa Clara wanted to hear. Bosa admitted it worried him at first.

"I've never had a calf, so I didn't really know," he said. "They told me they're pretty finicky sometimes, calves. But, actually, I checked with my brother (Joey), who had one last year in OTAs. He said three weeks, and he never even noticed it (after that)."

He said he has been doing two-a-day running sessions plus his normal lifts, and he feels like he turned the corner over the last few days. "I'm feeling better and better," he said.

The return timeline

The original plan left the door open to waiting until after the Nov. 1 bye. Bosa does not sound like a guy who wants to wait that long.

"But the fact that I'm already feeling like I could go out on Monday night and definitely not wait," he said. "Definitely Atlanta, possibly next week. Probably."

The Niners visit the Falcons on Sunday, Oct. 25, so the worst case he is describing is Week 7.

Who gets after Seattle's quarterback

There is real help coming on the edge. Kyle Shanahan said the team will activate Mykel Williams from the physically unable to perform list on Saturday, and the second-year end is slated to make his 2026 debut, per ESPN's Nick Wagoner. Williams tore his ACL on Nov. 2, 2025, against the Giants. "When he's out there, he'll be full go," Shanahan said.

Williams joins a rotation with Keion White, Khalid Kareem and rookie Romello Height. Receiver Mike Evans (ribs) has no designation and is good to go. Fullback Kyle Juszczyk (knee), safety Marques Sigle (ankle) and defensive tackle James Thompson (ankle) are out along with Bosa, and cornerback Upton Stout (shoulder) is questionable.

Seattle, meanwhile, gets Pro Bowl defensive lineman Leonard Williams back from an ankle scare, and safety Ty Okada returns from the hamstring injury that cost him the first four games, per Seahawks.com.

The bottom line

Going into Seattle undefeated without Bosa is a real test. If this defense can steal one at Lumen with Mykel Williams back and Bosa watching from home, the Niners get their best defender back for a Monday night run at Washington with a 5-0 record. That is about as good as it gets.