Where is Nick Bosa?

That was the question on everyone’s minds two weeks after the 49ers star edge rusher made the declaration that he would “definitely” be back for their game this Sunday in Atlanta.

Since his comments two Fridays ago, Bosa has yet to practice or even make an appearance during the portions open to the media. And on Friday, coach Kyle Shanahan confirmed that Bosa’s confidence had been misplaced — he was ruled out against the Falcons.

“I just think he was a little too optimistic,” Shanahan said. “Especially for Bosa because he’s pretty accurate. He doesn’t say stuff like that unless it’s accurate. I just think it surprised him.”

Bosa had made it back from ACL surgery to play in the 49ers’ first two games, recording seven tackles but no sacks, but made a surprise appearance on the injury report leading into their Week 3 game against the Cardinals. He strained his calf while warming up before practice on Sept. 24 hasn’t practiced since.

Two weeks ago, Bosa said that he was “feeling better and better” and that it was even “pretty darn likely” he could make it back in time for last Monday’s 23-17 win over the Commanders.

Now, the earliest the 49ers can expect to get Bosa back is Week 9, after their bye next week.

“He worked out after he said that and the next day he was just a little sore, which surprised all of us,” Shanahan said. “That wasn’t a great sign, especially going to play on turf this week.”

Although San Francisco will have to make do without Bosa for at least one more game, Raheem Morris’ defense has been A-OK without its star pass rusher. Despite zero sacks from Bosa, the 49ers are already three-quarters of the way to their league-last total from last season.

“I thought we’d have a chance to have a real good defense this year,” Shanahan said. “But when you lose six D-Linemen in the first two weeks, if you told me after that we’d still be a top-five defense going into Week 7, I would have been a little surprised.”

Rookies Romello Height and Gracen Halton, veteran acquisitions Osa Odighizuwa and Keion White, as well as practice-squad call-ups Sebastian Valdez and Ogbo Okoronkwo all have contributed multiple hits on quarterbacks, as well as mainstay Fred Warner.

“I think it’s a credit to everyone who has stepped it up,” Shanahan said. “It’s a credit to Raheem and the rest of those guys on the coaching staff. I’m real happy with how they’ve been working and playing and finding ways to win.”

Okoronkwo was released Friday to clear a roster spot for receiver Christian Kirk, but the 49ers are expected to re-sign him to the practice squad and elevate him to the active roster Sunday.