Tannehill completed 79.3 percent of his passes for 10.8 yards per attempt, for a 120.1 passer rating in his first start. Mariota hasn't come close to those figures all year. For the season, Tannehill owns the highest completion percentage (80.0), highest passing yards per attempt (10.1) and fifth-best passer rating 105.2 among all NFL QBs with at least 40 pass attempts.
Stats can sometimes mislead, and the sample size isn't nearly large enough to suggest we know Tannehill can be a short-term answer in Tennessee.
However, anyone who watched Sunday's game should have walked away with one obvious thought: Tannehill actually gives his receivers a chance to make a play.
Whereas Mariota was gun-shy, afraid to pull the trigger, taking sack after sack after sack, Tannehill drilled the pigskin into tight quarters. Mariota constantly made the annoyingly safe decision, deciding not throwing an interception was better than taking the chance to make a play. It's all well and good to protect the football, but sometimes that trait can hinder the entire operation. Tannehill showed there's a better method for moving the ball: Trust your receivers can make a play.
"I hope it gives them some confidence," Tannehill said of his performance, per the team's official website. "I can't speak for them on what they feel, but I know I have more confidence now throwing to those guys after seeing them go make contested catches in traffic. Corey (Davis) early in the game, A.J. (Brown) throughout the game just being able to attack the football and go get it. I told them like, 'Hey, you guys get open, I'm going to throw it. You guys attack the football and make plays,' and they did that.
"So, I know I have a lot more trust in those guys now that I've thrown those passes to them and I'm seeing them make the catches."
The difference in QB trust was stark. According to Next Gen Stats, Tannehill's targets had an average separation of 1.9 yards on Sunday. The lowest figure for Mariota on the season was 2.6 in Week 3 versus Jacksonville (when he was forced to throw a lot in a blowout loss). For the season, Tannehill's target separation of 2.5 is the lowest of any QB with more than 20 pass attempts. Mariota was averaging 3.2.
Target separation isn't everything, of course. Good offenses scheme open receivers so that QBs don't need to make tight-window throw after tight-window throw. But in the absence of wide-open targets, a signal-caller must be willing to thread the needle. Mariota wasn't. In the same offense, Tannehill showed that ability.
"Yeah, I expect it to continue to develop," Tannehill said of his rapport with his receivers. "The passing game is timing and trust, expecting those guys to be in the right spot at the right time. So, I have a ton of trust in those guys and I think I saw it happening in practice in training camp when I was able to throw to those guys a little bit. But really, just getting a week of practice under my belt with them only deepened that trust.
"I'm still one game in. (So I'm) just continuing to settle in with this offense, with this team, but I'm confident in the guys that are out there and expect things to just continue to gel together."
If the Titans' offense is able to be functional under Tannehill, Tennessee might have a chance to claw its way back into the AFC South race.