For a few anxious minutes last Sunday in Atlanta, the San Francisco 49ers had to picture the rest of their season without the engine of their offense.

Now that the swelling has settled and the tests have come back, Kyle Shanahan is speaking with more confidence.

He believes Christian McCaffrey dodged something serious, and he expects his star running back to be ready when the team comes back from its bye.

Speaking to reporters Monday, a day after the 29-20 loss to the Falcons ended San Francisco’s unbeaten start, Shanahan said McCaffrey’s injury was a mild hamstring strain. 

When asked whether McCaffrey should be available against the Las Vegas Raiders in Week 9, Shanahan didn’t hedge much. “Yeah, we think so, with it just being that,” he said, before adding the usual caveat: “You never know for sure, but we’re pretty optimistic about it. So is he.”

It was clear right away why McCaffrey’s health matters so much. He scored on the opening drive, finishing it with a one-yard touchdown, and his first few touches looked like the player who has carried this offense through a season full of injuries.

Before he got hurt, McCaffrey had 29 yards and a score on four carries and another 45 yards on three catches. He was gashing an Atlanta defense that had no answer for him.

Then, by his own description, his leg “just died on me.” He went to the sideline in the first half and came back after halftime, but he wasn’t the same player.

He managed 10 rushing yards and 16 receiving yards the rest of the way, and he finished with 100 total yards on 13 touches.

Without him at full speed, the offense fell apart. Jordan James fumbled, rookie Kaelon Black lost another fumble on the very next snap, and San Francisco gave the ball away four times in all.

If there’s a silver lining, it’s the calendar. A Grade 1 hamstring strain usually takes somewhere between one and three weeks to heal.

The 49ers don’t play again until November 8, when the Raiders come to Levi’s Stadium, so McCaffrey gets the full two weeks without missing a game.

The fact that he went back in and finished the game in Atlanta also suggests the injury is closer to a tweak than a tear.

McCaffrey’s possible return is part of a bigger wave of good news. Shanahan said Nick Bosa, Mike Evans, and Deebo Samuel all have a chance to come back after the bye.

He stressed that none of them are guaranteed, but the team could be close to whole for the first time in weeks, right as the November 10 trade deadline approaches and John Lynch decides how aggressive to be.

Still, none of that matters as much if McCaffrey isn’t healthy. He’s the player who has kept this team steady through all the injuries, and at 6-1 with a comfortable lead in the NFC West, the 49ers can afford to be careful.