INDIANAPOLIS -- The Indianapolis Colts' season has been relegated to this.

Their long-shot playoff hopes and their coach's fate could rest squarely on the shoulders of a quarterback who hasn't taken an NFL snap in more than two years against a team with more to gain by losing.

Four months ago, it was a scenario that seemed implausible. Now, after a series of strange twists and wrong turns sabotaged Indianapolis' season, the biggest problem could be on full display Sunday. Starting quarterback Andrew Luck, backup quarterback Matt Hasselbeck and third-string quarterback Charlie Whitehurst all conceivably could be watching Josh Freeman or Ryan Lindley playing Tennessee.

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"We've been through worse," coach Chuck Pagano said. "We've got a little issue at the quarterback spot, which some may look at and say, 'Gosh, how are you going to?' We'll find a way. It's going to be fun to watch."

And tough to survive with so many injuries.

Luck will miss his seventh straight game since being diagnosed with a lacerated kidney and a partially torn abdominal muscle. The 40-year-old Hasselbeck filled in nicely, winning his first four games before losing three of the last four and leaving all four with injuries. This week he's trying to bounce back from a sprained AC joint in his throwing shoulder.

Indy claimed Whitehurst off waivers from the Titans in November with the hope he could bail them out in a pinch, and he might have started this week had he not landed on injured reserve with a bad hamstring.

So after Freeman and Lindley signed with the Colts on Tuesday, they have been scrambling to learn the terminology, getting familiar with the game plan, and fighting to start in case Hasselbeck can't.

Regardless of who lines up behind center Sunday, Pagano figures the Colts must find a way to keep the Titans' defense off-balance.

"This is what we'll plan for is to have nine, 10 guys around the line of scrimmage on first and second down," Pagano said. "They're going to not let us run the football and dare us to throw it every snap. Once they get us in third down, then they're going to send the kitchen sink at us."

Tennessee's road hasn't been much easier.

The Titans (3-12) have lost six of their last seven (eight straight to Indy), endured a midseason coaching change and will play again without first-round draft pick Marcus Mariota. He's missing his second straight game with a sprained right knee.

Mariota's replacement, Zach Mettenberger, is 0-9 as a starter. If Mettenberger loses again, the Titans will get the perfect reward for an abysmal season: the No. 1 overall pick in the 2016 draft.

That's not what players are talking about, though.

"I can just see it in everybody that the energy is there and they understand we still want to try to win this one and go with some positive (energy) into next year," tight end Delanie Walker said.

Ruining their rivals' postseason chances would help, too.

But the Colts have defied the odds before, and Pagano figures if they can do it one more time, it would be a fitting finale.

"It's just the coup de grace. We wouldn't want it any different. I love it," he said. "I just can't wait to see what last chapter holds when it gets written 4:30 (p.m.) on Sunday."

Here are some other things to watch Sunday:

THE SCOREBOARD: Here's what it will take for Indy to make the playoffs: If the Colts win and Houston loses, the Colts need wins by Baltimore, Denver, Buffalo, Atlanta, Oakland, Pittsburgh and Miami.

THE HOT SEAT: Tennessee coach Ken Whisenhunt was fired in November, giving Mike Mularkey the always tenuous title of interim coach. The good news is that with one more win, Mularkey would match Whisenhunt's victory total (three) in 14 fewer games. Pagano, on the other hand, has dealt with speculation about his future all season. If this is the season finale for both teams, it shouldn't take long to learn what happens next.

THE GROUND GAME: If the backup quarterbacks struggle, this stalemate could be determined by the ground game, and it could be ugly. The Titans are No. 28 in rushing, averaging 3.9 yards per, and Antonio Andrews was responsible for two of four turnovers last week. Indy has been even worse: The Colts are No. 30, averaging 3.6 yards, and haven't had a 100-yard rusher since Dec. 16, 2012.

THE PUSH: The Titans spent a chunk of this season ranked among the NFL's best defenses. They head into the season finale ranked 13th in yards allowed and No. 7 against the pass. A good showing in Indy could push them back into the top 10, a marked improvement over last season's No. 27 ranking.

THE LONG GOODBYES? Indy's swoon could lead to roster changes, too. Hasselbeck, cornerback Greg Toler and kicker Adam Vinatieri all having expiring contracts. Receiver Andre Johnson and linebacker Trent Cole haven't met expectations. And although 34-year-old Robert Mathis has looked more like his younger self lately, there's no guarantee he'll be back in 2016.

Safety Michael Griffin could be playing his last game for the Titans, too. He turns 31 on Monday and would cost $6.5 million in 2016.