Ryan TannehillThe NFL is finally back. With training camps already underway, the Baltimore Ravens have begun their quest to repeat as champs while the other 31 teams have begun their mission to knock them off.

The first taste of live action comes Sunday night in the Hall of Fame Game. The Miami Dolphins and Dallas Cowboys — two renowned franchises that enter the 2013 season with high expectations — will start things off. Bettors will want to note that the Dolphins are a three-point favorite at Bovada with the total points scored in the game set at 33.

Each week of the preseason, we’ll run down the best prospects to watch and highlight the key positional battles of the week. Here’s a primer for the Hall of Fame Game:

Prospect Watch:

The prospects to keep an eye on this weekend will be Ryan Tannehill and Lamar Miller of the Dolphins, as well as Travis Frederick of the Dallas Cowboys (and their offensive line).

Starting with the Dolphins, people are going to want to see what Tannehill flashes in his second season as a starter. He showed potential last season and has earned rave reviews in training camp, but the numbers don’t lie: 12 touchdowns, 13 interceptions and a 76.1 passer rating (his numbers from 2012) won’t cut it in this league. He’s not likely to play much, but onlookers will want to see progress — especially since he has a number of new weapons to work with.

A lot of fantasy guys will be watching his backfield mate Miller, who will be a first-time starter this year. He’s entering his second season and has proven to be an explosive runner in limited opportunities. With Reggie Bush gone, he’s the main man. Durability issues plagued him at the University of Miami, and he’ll have to prove he can handle a full workload — starting Sunday.

Monitoring the Cowboys will be less exciting because their 2013 first-round pick is center Travis Frederick. Watching an offensive line isn’t particularly breathtaking. However, the Cowboys 2012 season was torpedoed by pathetic offensive line play as the team produced the fewest rushing yards in franchise history and allowed quarterback Tony Romo to get sacked a career-high 36 times.

The hope here is that Frederick solidifies the unit, giving them a better shot at making it to the Super Bowl (they currently have just 33-1 odds of doing so). The Dolphins have a stellar pass rush, so we’ll see if the Cowboys offensive line is any better right off the bat.

Key Positional Battles:

The Cowboys are transitioning their defense from a 4-3 to a 3-4, and while that bears watching, the main battle in Cowboys camp is at free safety. Veteran Will Allen is battling rookie J.J. Wilcox, who opened some eyes in minicamp. Some live action will help decide this starting spot.

For the Dolphins, their main position battle is also in the secondary. Brent Grimes looks like he’ll be one starter at cornerback, but veterans Richard Marshall and Dimitri Patterson are fighting for the second starting job. The Dolphins picked off just 10 passes last season (29th in the NFL), so they’re hoping that some competition fuels more turnovers.

Coaching Trends:

Both Joe Philbin and Jason Garrett enter the 2013 on the hot seat. Garrett is feeling a little more heat than Philbin at this point as his Cowboys have disappointed in each of the last two seasons. Meanwhile, Philbin is only in his second season, but head coaches don’t get much time to rebuild (see: Mike Mularkey). Philbin will need to deliver results after ownership spent nearly $250 million on personnel this offseason. Miami’s regular season win total is set at 8 with under paying out at -125.

Philbin is 0-4 in his career in the preseason while Garrett sports a record of 5-3.