HOUSTON (AP) — The Baltimore Ravens will need some help to clinch a playoff spot on Sunday.

But a win against the injury-plagued Houston Texans will certainly bolster their chances of reaching the postseason no matter what happens.

The Ravens (9-5) can secure a playoff spot with a win and losses by both Pittsburgh and Cincinnati, or a win and losses or ties by both Kansas City and San Diego, or a tie and losses by Kansas City and San Diego and a loss or a tie by Buffalo.

Coach John Harbaugh doesn't have to remind his team how competitive the AFC North is; three of four teams have nine wins.

"They know. They know how tight it is," Harbaugh said. "They know what they have to do."

The Texans (7-7) have a slim chance of reaching the playoffs, too, but would need to win both remaining games and for several teams to lose their last two.

They'll proceed with a fourth-string quarterback with Ryan Mallett (chest), Ryan Fitzpatrick (broken leg) and rookie Tom Savage (knee) all out with injuries. Coach Bill O'Brien won't say who he plans to start between Thad Lewis and Case Keenum.

"We don't know who we're going to play," Baltimore outside linebacker Elvis Dumervil said. "All we can do is just kind of gather up film and try to prepare for everything ... so, it's difficult. As difficult as it may seem for them, it's difficult for us, too."

But regardless of who O'Brien picks, the Ravens will face a quarterback who hasn't appeared in a game this season — and who wasn't with the Texans when the season began.

Because they don't know who'll start at quarterback, the Ravens are focused on slowing down Arian Foster, who is averaging 102.5 yards rushing a game.

Keenum lost all eight games he started for Houston last season before being released in training camp. Lewis went 2-3 in five starts for Buffalo in 2013 before he was released in camp. The Texans plucked Keenum off the St. Louis practice squad this week and signed Lewis on Nov. 26 when Mallett was injured.

"These guys have stepped right in, and it's really the philosophy in this league, that injuries happen and the next man up has to be ready to go," O'Brien said. "Both guys are working really hard."

Some things to know about the Ravens-Texans game:

HOMECOMING: Sunday will be a homecoming for Baltimore offensive coordinator Gary Kubiak, who grew up in Houston and coached the Texans from 2006 until he was fired last year. Kubiak led the Texans to the only two playoff appearances in franchise history in 2011 and 2012.

Many of the Texans are excited to see their former coach again, but Foster is looking forward to it more than most. Foster, an undrafted free agent, said he'll always be thankful to Kubiak for giving him a shot in the NFL.

CORNERED: The Ravens have five cornerbacks on injured reserve, which goes a long way toward explaining why they have the NFL's 30th-ranked pass defense. Six players have lined up at cornerback for Baltimore, which last week lost two defensive backs — CB Asa Jackson and safety Terrence Brooks — to knee injuries.

WATT A SEASON: Houston defensive end J.J. Watt keeps adding to his impressive numbers. Watt had two sacks last Sunday to give him 16 ½ this season, third in the NFL. He has 53 career sacks to tie the franchise record and needs 3 ½ more to become the first player in NFL history with two seasons with 20 or more sacks; he had 20 ½ in 2012. He has swatted down 10 passes, forced three fumbles and recovered five.

He's also scored on an interception return, a fumble return, and has grabbed three touchdown receptions.

HOMECOMING, PART 2: Kubiak isn't the only Raven with ties to Houston. Veteran tight end Owen Daniels returns after spending the previous eight seasons with the Texans.

"It's going to be weird walking into that stadium," he said. "It will be different being in there and coming out a different tunnel and all that stuff. But it will be good to see my old buddies that are still there."

Daniels signed as a free agent with Baltimore in April.

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AP Sports Writer David Ginsburg contributed to this report.

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