SANTA CLARA, Calif. -- The San Francisco 49ers are in trouble. Big trouble.

After a disappointing loss last week to the Philadelphia Eagles, the Niners needed to make a statement on Sunday against the Miami Dolphins. And they did. It read something like this: Barring a major and expedient turnaround, this season is slipping away in a hurry.

The banged-up 49ers were flat from the beginning in an embarrassing 43-17 blowout loss to the Dolphins. It was a performance the likes of which hadn't been seen in these parts in at least a couple of seasons. Miami receivers ran free for huge plays, the Niners' offensive line offered little time to throw, the once-vaunted San Francisco pass rush was mostly nonexistent and quarterback Jimmy Garoppolo was benched.

Yes, the 49ers are dealing with more than their share of injuries. They started Sunday's game without all three of their top cornerbacks, leaving practice squad player Brian Allen to start and endure a brutal performance. But this was supposed to be the 49ers' get-right game in which their key offensive performers were all together for the first time and would lead them to a win before entering a brutal stretch of schedule.

Instead, it was the Niners' second consecutive loss, dropping them to 2-3 and into sole possession of last place in the NFC West division.

Now, they enter what is arguably the most difficult stretch of schedule any team will play this season. Over the next seven games, the 49ers will host the Los Angeles Rams, travel to play the New England Patriots and Seattle Seahawks, return home against the Green Bay Packers, go to the New Orleans Saints and Rams and host the Buffalo Bills.

The Niners believe they have built something special and sustainable in the past few years. If that's true, they'll have ample opportunity to prove it in the coming weeks.

QB Breakdown: Garoppolo's return from a high right ankle sprain lasted one half and, like the rest of the game, it wasn't pretty. Garoppolo never looked comfortable as he was under siege for much of his time on the field and finished 7-of-17 for 77 yards with no touchdowns and two interceptions for a passer rating of 15.7.

Backup C.J. Beathard had a little more success, going 9-of-18 for 94 yards with a touchdown, but the game was out of hand by the time he stepped on the field.

Describe the game in two words: Never close. The Niners looked lifeless from the outset and never really threatened the Dolphins, something that would have been difficult to imagine in August.

Troubling trend: The Niners' offensive line and pass protection was once again abysmal. Miami had pass-rushers and blitzers running free at Garoppolo and Beathard for most of the game. And although the run blocking was better, it didn't matter because the 49ers fell so far behind that they mostly abandoned the run altogether. Miami finished with five total sacks and eight quarterback hits.