NASHVILLE, Tenn. -- The Titans face the Miami Dolphins in the season opener on Sunday at Hard Rock Stadium.

Here's a look at six things to watch:

A new Mariota?

OK, so we've already seen Titans quarterback Marcus Mariota play three seasons – in 42 games, to be exact. We also saw him in the preseason – in seven drives, to be more specific. But we haven't seen him in Matt LaFleur's offense in a regular season game. This week, the Titans offensive coordinator smiled and cracked a joke when asked if he's ready to pull back the curtain on his new offense in Tennessee. Mariota will be standing there, of course. How will it look? And how will Mariota perform in a new-look offense?

1-2 punch

The question I got most this offseason wasn't about Mariota, the new offense, or new head coach Mike Vrabel. Early in the offseason it was about the new uniforms, but once they were unveiled it changed to the running backs. What will the division of carries look like between Derrick Henry and Dion Lewis? Which back will be on the field more? I suspect it will be a week-by-week thing, depending on how teams defend the Titans, and how the backs perform. I do know this: The Titans need to establish the running game on Sunday against a Dolphins defense line that would love to pin its ears back and go after the QB.

The young receivers

The Titans head into Sunday's game with a lot of inexperience at the receiver position. Behind Rishard Matthews, receivers Corey Davis, Taywan Taylor and Tajae Sharpe all have just one season of NFL experience. The Titans need them to grow up fast. Having other passing game options – from Lewis to tight ends Delanie Walker and Jonnu Smith – and a formidable running game helps take the pressure off the bunch to some extent. But the Titans are going to need the young guys to handle the pressure, while getting a handle on the football.

The pass rush

Quarterback Ryan Tannehill is back in the saddle for the Dolphins, and he can move around. Like the Titans, the Dolphins want to run the ball with Kenyan Drake and Frank Gore. But Tannehill has some weapons to throw to himself, even with the expected absence of receiver DeVante Parker. Big and athletic tight end Mike Gesicki will be a tough guy to defend. The Titans need to disrupt things by making Tannehill uncomfortable, and it's going to take a group effort. With injuries at outside linebacker, the Titans will need guys like Brian Orakpo and Kamalie Correa to play a lot of snaps, and the hope is Derrick Morgan can join Aaron Wallace in the attack as well. The Titans also need defensive lineman Jurrell Casey and Co. to create some havoc to keep Tannehill from settling in.

The heat and humidity – and possibly rain

When I tweeted out a picture of safety Kevin Byard in the light blue uniforms the Titans will wear on Sunday, I got a lot of wise cracks from Dolphins fans in South Florida about how the light colors won't keep the Titans from baking. The reality is, the Titans have dealt with just as much heat this summer as the Dolphins. Nonetheless, the heat can't be ignored, because it will test the conditioning and stamina of players. The heat didn't bother the Titans as they wore down the Jaguars in a September game in Florida last year. Which team best handles the heat – and potentially some wet conditions – will go a long way in determining who comes out on top.

Mike Vrabel's debut

Vrabel knows Sunday isn't about him. He's a guy who excelled in New England's team-first mindset, so he'd rather keep himself out of the storylines. But this is one that can't be ignored. Vrabel will make his head coaching debut on Sunday, and he'll deal with some things he's never tackled before, from setting a pre-game tone, to overseeing operations, to potentially challenging calls. He'll let his coordinators do their thing, but he'll be running the show. How he handles life under the headset will be on display beginning on Sunday.