Editor's note: The Tennessee Titans and quarterback Ryan Tannehill agreed to a four-year contract extension on Sunday, March 15. This story was originally published on Jan. 16, 2020.

NASHVILLE, Tenn. -- Ryan Tannehill once envisioned himself being a Miami Dolphins lifer, something no quarterback has done for the franchise since Dan Marino from 1983 to 1999.

But after seven years in South Beach, Tannehill's wish dissipated. The Dolphins didn't want him anymore. Miami's new regime traded him to the Tennessee Titans for a couple of late draft picks. It was a career low point for Tannehill.

Low points can eventually give way to high points. One year later, Tannehill has had a "made for Hollywood" comeback season with the Titans, leading the NFL during the regular season in passer rating (117.5). The Titans are in Sunday's AFC Championship Game (3:05 p.m. ET, CBS) for the first time since the Steve McNair-Eddie George era in 2002 and 2003.

Tannehill is one win away from playing in Super Bowl LIV, to be held on Feb. 2 at Hard Rock Stadium in Miami Gardens, Florida -- the same place he called home for seven years.

Now 31, the quarterback smirks at the suggestion it would be a poetic bookend. From a Dolphins discard to a Titans treasure; it sounds like a storybook season. However, it didn't start that way in Nashville.

It took time for Tannehill and his family to adjust to their new home. Tannehill also had to adjust to being a backup for the first time in his eight-year pro career, which called for a mix of patience, pain and short-term sacrifice.

"It was really hard. Nobody likes to sit on the bench. I wanted to be playing. I wanted to be competing. Everything is different when you're not in the starting position," Tannehill told ESPN. "That was a big change for me. There was a lot of biting your tongue and swallowing your pride. It was definitely an adjustment. But I just tried to make the best of the situation I was given, play my role and be a good teammate."

'You've got the keys now'

It's a surprisingly warm, humid Wednesday in Nashville as the Titans prepare to slay their third giant in as many playoff weeks -- this time taking on quarterback Patrick Mahomes and the Kansas City Chiefs.

Tannehill trots out of the locker room and onto the practice field unfazed at the challenge ahead. Running back Derrick Henry is the workhorse and face of the Titans' offense, but it's Tannehill's team now and he knows it.

Titans general manager Jon Robinson had a list of expectations for Tannehill when the veteran took over the starting job from Marcus Mariota last October.

"Go play starting-level football. Take command of the offense. You've got the keys now," Robinson told ESPN of his message to Tannehill. "Get us in the right play at the line of scrimmage. When you've got to throw the ball, identify the coverage, find the guy that's open and get him the football. Keep plays alive. Move the football. He did a great job. You saw his personality and leadership come out even more."

Promoting Tannehill might be the decision of the season by coach Mike Vrabel. Mariota had been the face of the Titans and unquestioned starter since he was selected No. 2 overall in the 2015 NFL draft. But with the team at 2-4 and on the brink of falling apart, Tannehill got his turn.

"Marcus has my utmost respect. He's been the perfect professional. He's such a good dude and teammate even though his role has changed," receiver Tajae Sharpe said. "It was a tough situation, but the coaches decided it was the right decision to help the team. Ryan did a great job of leading us once he came in. He was very vocal and upfront about what he wanted from us on certain routes as a receiving group. He fits in perfectly with this team. He definitely has a swag to him, too."

Since Tannehill took over in Week 7, the Titans have ranked third in points per game (30.4), yards per game (406.2) and offensive efficiency (72.6). Since Week 9, the Titans have scored 39 offensive touchdowns and one field goal.

"On Oct. 14, we were 2-4. I was a bad coach, and this was a bad team," Vrabel said. "We tried to believe in each other, we tried to improve, tried to prepare, trust each other, execute. That's what's gotten us here, so we can't change and start to make things up now."

Tannehill is the third quarterback since 1991 to finish the regular season with both a completion percentage and red zone completion percentage at over 70% (Drew Brees, 2018; Steve Young, 1994).

"Ryan has an undying belief that we are going to score every time we get down there, and he should. Every quarterback should," Titans quarterbacks coach Pat O'Hara said. "We started working hard on our red zone efficiency in the spring. It's paying dividends now."

'Do what's best for the team'

One of Robinson's go-to mantras describes how he builds the Titans' roster. He seeks players who are willing to "do what's best for the team, even if it's not in your best individual interest."

So when "Trader Jon" -- as he's known in some NFL circles -- got wind that the Dolphins were looking to move on from Tannehill in late February, Robinson called Dolphins general manager Chris Grier to talk a deal.

After trade parameters were agreed upon and Robinson received permission to renegotiate a deal with Tannehill's reps, the last step was seeing if Tannehill would do what's best for the team -- even if he wasn't thrilled with being a backup to Mariota. Tannehill agreed.

"Ryan was a guy who had played a lot of good football, started games, won games in this league. I've admired him from afar," Robinson said. "I was direct in defining what the role was with him with Marcus on the roster. I told him he would be the backup but 'you're coming in here to compete. You never know how things will shake out.'"

The Dolphins essentially bought the 2020 fourth-round pick they received in exchange for Tannehill by paying $5 million of the veteran QB's reworked $7 million 2019 salary. Tannehill, who is set to be a free agent this spring, also received more than $2 million in incentives from the Titans for his 2019 performance.

As Tannehill learned from Mariota, ran the Titans' scout team and supported the team, he promised himself he would take advantage of his next opportunity.

"I love competing. Whether football or board games, I love to win," Tannehill said. "My wife gives me a hard time, whether it's playing games with people we don't know too well and I'm intense. I could probably turn off a few people to probably being around me because of that.

"When what you love is taken away from you and you're not getting to do what you love, the monotonous things you often took for granted are what you really miss. Once I started playing again, I appreciated the small moments again."

To his credit, Mariota did what was best for the team, even if it wasn't in his individual interest.

When the Titans made Tannehill their starting quarterback, they had less than a 0.1% chance to win Super Bowl LIV, per FPI. Now they have a 12% chance. Tennessee, seven-point underdogs to the host Chiefs, has already beaten the NFL's top scoring offense (Ravens) and top scoring defense (Patriots) this postseason. They are the third team since the 1970 merger to beat the top scoring offense and defense in the same postseason. The other two teams that did it -- 2004 Patriots and 1988 49ers -- won the Super Bowl.

"All the stars are aligning for Ryan right now. It's not just because of Derrick Henry. Ryan's a great player, too. The change of scenery has helped him a bunch," Houston Texans receiver Kenny Stills, who played with Tannehill in Miami from 2015 through 2018, told ESPN.

Tannehill was perfect for the Titans' physical, no-nonsense culture. Vrabel refers to his team as "street rats" because of how hard they play, and Tannehill fits in that group, too.

"He's athletic. He's accurate. He's prepared. He's a really good leader," Vrabel said. "He's been able to hold players accountable in his own way. I'm glad we have him on our team."

'You can't hold on to the past'

It was a cold December 2018 afternoon in Buffalo with the clock winding down on what would end up for the Dolphins being a season-ending blowout loss to the Bills. Time was running out on the most recent era in Dolphins football under former coach Adam Gase and everyone knew it.

During the Dolphins' final fourth-quarter drive, Tannehill told teammates in the huddle: "I've appreciated every moment with you guys. It was an honor to be your quarterback."

Two and a half months later, Tannehill was traded to the Titans. The change marked a new beginning for Tannehill and the Dolphins -- who saw their up-and-down tenure together end with a 42-46 record, one playoff appearance, a mix of nostalgia and underachieved potential. The fan base largely cheered his exit, even though Tannehill was arguably the franchise's best quarterback since Marino.

"If you're a football fan and pay attention to the details of the quarterback position, then you appreciated Ryan," Stills said. "If you're a Dolphins fan and don't have respect for him, I don't know what football you were watching.

"To be a part of a team that was booing him off the field at one point, it was hard to hear. In his mind, I'm sure he doesn't have to show anybody anything. He's confident in the player and man that he is. But, I'm sure it would feel good to go to Miami and play in the Super Bowl down there."

Dolphins owner Stephen Ross seemingly spoke for much of the fan base at last year's annual owners meetings when he said: "I love Ryan. But you're right, how many years was it? It was time to move on."

Tannehill heard the comments. He's not sure if he agrees with the timing sentiment, but he also acknowledges it was never his decision to make.

"You just sort of take it and move forward. Obviously, we liked being in Miami and Steve was good to us during our time there. They decided to move on. So, you have to move on," Tannehill said. "You can't hold on to the past. I just told myself I've got to do the best with the new opportunity that is in front of me."

Like a storybook ending, Tannehill's newfound success could put him face-to-face with the past he had no choice but to move on from. Tannehill recognizes the meaning of reaching Super Bowl LIV in Miami.

"I've definitely thought about it. It would be cool. I realize that's the next step. It'd be cool to play in that stadium. I know that stadium, obviously, really well," Tannehill said. "Then, I reel it back in. I don't go down that road too far. It doesn't matter what's next week if we can't win this week, so let's win this week."