NASHVILLE, Tenn. >> The Titans have assured themselves of a third straight winning season for the first time since moving to Tennessee, and the NFL’s longest current winning streak has them playing the final game of the regular season with a playoff berth on the line.

They’ll find out Sunday night if that’s enough to sell-out their home stadium with Titans fans.

Safety Kevin Byard believes they’ve done enough to convince fans to turn out.

“You have a team that’s playing for a playoff spot, be one of the few teams that’s going to be in the postseason,” Byard said. “I think that’s every motivation that everybody in Nashville should be in Nissan Stadium. I think we’ve done a great job this year and previous years. This game is a playoff game, and I think it’s something we’re trying to make history right now.”

The Titans (9-6) will host Indianapolis (9-6) in a win-and-in prime-time showdown on Sunday night; the loser is done for the season. The Titans and Colts will play for at worst the AFC’s second wild-card spot and the sixth overall seed with the AFC South title possible if Jacksonville beats Houston.

Crazier still, losses by Houston, Baltimore and New England could leave Sunday night’s winner not only as a division champ but the No. 2 seed with a first-round bye.

It’s almost unimaginable for the Titans after being 5-6 and fighting to get to .500 when December started. Now the Titans have won four straight to climb past teams like Cincinnati, Denver, Miami and now Pittsburgh. Only the Colts stand in their way now.

“We all can recognize we’ve been in the playoffs now going on five weeks, we’ve been in the playoffs for the past four weeks,” coach Mike Vrabel said.

The Titans will have to wait and see if Marcus Mariota is available after a stinger knocked the quarterback out of their 25-16 victory over Washington on Saturday. That was the third game Mariota couldn’t finish this season and seventh of his four-year career.

Vrabel said Mariota felt better Monday than the quarterback did after his last stinger Nov. 18 in a 38-10 loss in Indianapolis. Mariota didn’t miss a start, but the Titans did bring back quarterback Austin Davis who spent two weeks on the active roster in September.

Mariota, a Saint Louis alumna, and the Titans are in a similar situation with an extra day to recover between games. Vrabel said they planned to test Mariota on Monday with individual drills while making sure through the rest of the week that the quarterback can do everything needed to play.

But the Titans will be without four-time Pro Bowl defensive tackle Jurrell Casey after they placed him on injured reserve Monday with a knee injury aggravated in the fourth quarter against the Redskins. Casey is the second

One more win ensures a second straight playoff berth for the Titans for the first time 2007 and 2008. This franchise hasn’t won five straight since 2009 when the Titans reeled off five straight after starting the season 0-6. This also will be their first Sunday night game since Oct. 11, 2009, when they lost to the Colts 31-9.

Safety Kenny Vaccaro has never played in the postseason. He broke his ankle as a rookie with New Orleans and tore an abductor muscle last year.

“This is like my first playoff game, so I’m excited,” Vaccaro said. “We’ve been in the playoffs the last four weeks if you think about it. Not too long ago we were 5-6 just trying to get back to .500.”