The San Francisco 49ers have a new claim to make in the NFC West, and Brock Purdy is the reason why.

Through three weeks, the 49ers quarterback has thrown for 9 touchdowns against just 1 interception, completing 72.3% of his passes for 789 yards at a ridiculous 9.51 yards per attempt. Those are MVP-caliber numbers by any measure, and they have San Francisco sitting atop the division with a 3-0 record despite a roster that keeps getting thinner.

Purdy is thriving with a depleted supporting cast

What makes Purdy’s start so impressive is the context around it. The 49ers have lost De’Zhaun Stribling to injury. They’ve lost Jake Tonges. Demarcus Robinson is out. Trent Williams barely played in Sunday’s game due to an injury.

And yet, Purdy keeps slinging the rock at an elite level.

The veterans around him deserve credit. Christian McCaffrey has reclaimed the lead back role, handling 15 touches to Kaelon Black’s four on Sunday. George Kittle is back and producing. And Deebo Samuel has returned to insane relevance, highlighted by a hook and ladder play that gave him 80 receiving yards with zero receptions, shattering the NFL record for most receiving yards without a catch.

That stat may never be broken.

This is the core of the group that carried San Francisco to two Super Bowl appearances, and the “unks” still have it. McCaffrey looks like McCaffrey. Kittle is Kittle. And Purdy is orchestrating the whole thing at a level this offense may not have reached in a long time.

The defense raises legitimate questions

For all the offensive fireworks, the 49ers defense just allowed 30 points to Jacoby Brissett and the Arizona Cardinals on Sunday. That is a real concern.

If San Francisco is going to keep giving up points at that rate, Purdy and the offense will need to win shootouts on a weekly basis. That is a tall order over the course of a full season, regardless of how well the quarterback is playing.

Throwing some water on the MVP hopes

As good as Purdy has been, there is context to these numbers that deserves acknowledgment.

In the Week 1 win against the Los Angeles Rams, he threw 3 touchdown passes but averaged only 6.03 yards per attempt in a game played across the world that felt like a strange first week of action. Since then, the 49ers have beaten up on the Miami Dolphins and Arizona Cardinals, neither of whom profiles as a top-tier defense.

Purdy is a baseline good quarterback, and he will continue to put up strong numbers. But the schedule is going to stiffen. Better football teams are coming. There is a very real chance that these numbers return to the mean at some point, and the MVP conversation could look different when that happens.

The injury situation also threatens the offensive ceiling. Mike Evans is banged up. Two All-Pros have already missed time. Kittle is back, which is great, but the 49ers cannot keep losing key pieces and expect to sustain this level of production indefinitely.

The Rams are not dead yet

It would be premature to bury the Los Angeles Rams after an ugly late loss to the Denver Broncos. That game was in Denver, and the Rams were missing significant pieces. The NFC West race is far from settled, even with San Francisco’s hot start.

Brock Purdy has been very good through three weeks, and the 49ers offense is humming in a way that could change the landscape of the NFC West and perhaps the entire NFC. Sustainability is the question that hangs over everything, from the injuries piling up to the defensive concerns to the quality of opponents on the horizon.

San Francisco looks like the division’s top dog right now, but holding that title through a full season is a different conversation entirely.