The Tennessee Titans report to training camp on Friday at Saint Thomas Sports Park in Nashville. Here's a closer look at the Titans' camp:

NFL Training Camp Coverage Who's on the bubble? Which rookie could surprise? NFL Nation reporters take a crack at a preliminary 53-man roster and starting lineup projection and preview what to expect in training camp for every team.

Top storyline: General manager Jon Robinson has put the Titans in position to be successful for years to come by providing the necessary pieces for franchise quarterback Marcus Mariota to lead them. It started with an offensive line to protect Mariota (tied for seventh in fewest sacks allowed last season), then the addition of running backs DeMarco Murray and Derrick Henry (third in team rushing yards), and Robinson addressed the defense this offseason. Tennessee added former New England Patriots cornerback Logan Ryan and former Jacksonville Jaguars safety Johnathan Cyprien to a defense that finished 20th in the NFL last season. It's a matter now of whether the Titans can put it all together to compete with the Houston Texans and Indianapolis Colts, the only teams to be AFC South champion the past eight seasons, in the division.

QB depth chart: The Titans have a proven backup behind Mariota, who is coming off a broken right fibula suffered in Week 16 last season, in veteran Matt Cassel. Cassel is more than capable to step in if Mariota suffers an injury. Cassel has thrown for 17,287 yards during his 13-year career, which has included stops in New England, Kansas City, Minnesota and Dallas. Alex Tanney is the third quarterback on the depth chart.

The Titans drafted two receivers in the first three rounds, meaning Harry Douglas has been put on notice. AP Photo/Chris O'Meara

Bubble watch: It's time for receiver Harry Douglas to start looking over his shoulder. He took a $2 million pay cut in the spring, and then the Titans selected receivers Corey Davis and Taywan Taylor in the first and third rounds of the draft. Last season Douglas had only 15 receptions for 210 yards, which was just sixth on the team in both of those categories. Those types of numbers won't keep Douglas on the roster.

That rookie could start: The Titans didn't use the fifth overall pick in the draft on Davis for him to be sitting on the sideline. The speedster will be Mariota's primary deep threat after he had 52 touchdowns and averaged 15.9 yards a reception during his four-year career at Western Michigan. Davis' big-play ability will force defenses to be honest when they try to load the box to stop the run.

Tough start: The schedule doesn't do the Titans any favors at the start of the season. Not only do they play three of their first five games on the road, but four of their first five games are against teams that made the playoffs last season. A slow start for a team that hasn't made the playoffs since 2008 could make for a tough hole for the Titans to climb out of later in the season.

Mariota money in red zone: Get to the red zone, and it's highly likely that the Titans will have success. Mariota, who had only nine interceptions last season, has thrown 33 touchdowns with no picks while completing 64 percent of his pass attempts in the red zone in his career.

For daily updates at camp, check out the Titans clubhouse page.