BALTIMORE -- Did the Baltimore Ravens save their season or did they take a hit that could derail it?

The Ravens' 40-0 rout over the Miami Dolphins was their most impressive performance of the year, stopped a season from spiraling out of control, and evened their record at 4-4.

But the lasting image Thursday night was quarterback Joe Flacco taking a gruesome shot to the head and walking off the field while bleeding from his left ear.

It's uncertain how long Flacco will be out with a concussion. What is known is he's the one player they could least afford to lose.

"We've had a lot of injuries this year, so our guys know how to handle it," coach John Harbaugh said. "We expect there to be no drop off. Everybody else rallies to make sure that happens."

The Ravens have 10 days to regroup before playing at the Tennessee Titans on Nov. 5 and then go on a bye. Ryan Mallett, who had struggled mightily in training camp and the preseason, finished 3-of-7 for 20 yards and one touchdown.

Baltimore has played only six games since the start of the 2008 season without Flacco, going 2-4 in finishing the 2015 season. It could be an even bigger test to line up without Flacco this year with an offense that has already lost starting guards Marshal Yanda and Alex Lewis as well as tight end Dennis Pitta for the season and are currently without wide receiver Mike Wallace (concussion).

"Going forward without him is going to be a big challenge to the offense," offensive tackle Ronnie Stanley said. "But it's something we're very capable of handling."

In what turned out to be a cruel twist, Flacco was having his best game in a career-worst year before he was knocked out with three minutes left in the first half. Scrambling for one of the few times this season, Flacco ran 9 yards and then decided to go down a yard short of the first-down marker. As he was sliding, he was hit in the head by Dolphins linebacker Kiko Alonso, causing his helmet to fly off as well as a cut on his ear that later needed stitches.

Baltimore showed little mercy in running up the score against the team that knocked out its quarterback. This was the largest shutout victory in the franchise's 22-year history.

"We're very passionate about our team and protecting the quarterback," running back Alex Collins said. "So just seeing him go down like that, I could just see in everybody's eyes that we wanted to finish this game strong for him."

Without Flacco, the Ravens are going to lean heavily on the physical running of Collins (career-best 113 yards), the playmaking ability of their defense (two defensive touchdowns) and the All-Pro kicking of Justin Tucker, just as they did Thursday night.

Baltimore has little margin for error going forward. Entering this game, the Ravens had a 26.3 percent chance to make the playoffs and 4.1 percent chance to win the division, according to ESPN Analytics.

This has been one of the most painful seasons in the Ravens' existence. Baltimore has placed 15 players on injured reserve and entered this game with 16 players on the injury report.

But none of those injuries compare to the one suffered by Flacco. A challenging season suddenly got heightened even more.

"The challenge going ahead is that you have eight [games] left," linebacker Terrell Suggs said. "You can't go .500 out of those eight. You definitely have to take care of the game you are supposed to win. You have to play some ferocious football down the stretch."