DAVIE, Fla. -- On Sunday, Ryan Tannehill will play a meaningful NFL snap for the first time in 637 days. He has faced every emotion you can think of in the time between Dec. 11, 2016 and now. He's ready to play football again.

"Sunday is going to be huge," said Tannehill, entering his seventh NFL season. "Obviously, I haven't got to play a full game in a long, long time. To be able to do it at home in front of our fans and go out and do what I love, it’s going to be a lot of fun."

After a taxing rehab after surgery to repair a torn ACL and watching chaos envelop the 2017 Dolphins, Tannehill has a new perspective. He has become more open, free and confident. It's clear from the way the 30-year-old quarterback addresses his teammates to his active social media presence, evidenced by a recent unprompted video Q&A session with fans on Twitter.

Tannehill knows the success of the Dolphins' 2018 season depends greatly on how he performs and his ability to stay healthy. It appears to be a make-and-break season for Tannehill, but he doesn't appear overwhelmed by the pressure or added responsibility. Instead, he has started to embrace a more vocal leadership role.

"I feel more confident in fully playing the position than I ever have," Tannehill said.

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Dolphins coach Adam Gase added: "Ryan was drafted here. This is his team. There's a pride factor there. This organization means a lot to him. He gets hurt. He didn't go anywhere. He knows there is a lot of faith in him from ownership on down. He knows we all have his back. He knows we are here to help him be better and a leader and help direct this team because that's what we need at that position."

Tannehill's confidence has shown through during practices this season. Perhaps not coincidentally, it mirrors Gase's sharp confidence. The coach and quarterback have been tight and particularly aligned this offseason. That chemistry appears to have trickled down to the locker room. It often creates fun moments such as Wednesday, when Gase compared 2016 Tannehill to the current one.

"Now he grabs hold of the reins and takes over practice and he's all riled up. [Wednesday], I figured out a way to upset him a couple of times, which is always great," Gase said. "He was wired in. It was fun going through [Wednesday] as a whole -- the meetings, the practice, all of that stuff."

As far as the injury, there have been no apparent signs of Tannehill favoring that left knee, aside from the brace that he wears on it as a precaution. The Dolphins won't be afraid to use him on bootlegs, outside-the-pocket throws or read-option plays.

Several Dolphins players said they believe Tannehill is back to where he was in 2016 before the injury. That year, he completed 67.1 percent of his passes for 2,995 yards, 19 TDs and 12 interceptions before suffering that season-ending ACL injury in his 13th game. He opted for treatment instead of surgery and attempted to come back in training camp last summer, but reinjured the knee in practice on Aug. 3, 2017.

Tannehill had the highest completion percentage, passer rating and yards-per-attempt in his career in 2016, his first year under Gase.

"Offensively, having Ryan back has been so valuable for us," Gase said. "Not having Ryan last year opened up a lot of guys' eyes that he made a big difference for us. He did it quietly in 2016. He started being more vocal in 2017, then he was out for the year. He's at the part of his career where he's not afraid to say what he wants to say and his delivery is good on relaying what he needs to without starting a forest fire."

That first regular-season snap will be special. Tannehill probably will quickly reminisce about all he has had to overcome. Then it's on to trying to beat the Tennessee Titans.