NFL Nation's Todd Archer examines the three biggest issues facing the Dallas Cowboys heading into training camp:

The health of Romo: Ever since he became the starter in 2006, how Tony Romo goes is how the Cowboys go. He is coming off his second back surgery in less than a year, but he was able to do much more this offseason than he did in 2013, when he had a cyst removed. The Cowboys kept Romo out of any competitive drills in the spring in order for him to be fully healthy by the time they got to training camp. Using last year's camp as a guide, Romo did not miss a day of work, and the Cowboys don't believe he will need to be eased into the full practice load this summer either. Because a big part of Romo's game is his ability to move and create in open space, however, they will be cautious if there even hints of more soreness than just the aches and pains of training camp. All offseason, the Cowboys have not expressed any worry about Romo, who turned 34 in April, being able to return to form. He will get his first chance to show it on the practice fields in Oxnard, California. If he can play at a high level -- he had 32 touchdown passes and 10 picks in 15 games last season -- then the Cowboys should be able to contend for a playoff spot in a division that is not as strong as it has been in the past.

Marinelli to the rescue: The Cowboys' defense was historically bad in 2013, and they enter this season without their all-time leader in sacks (DeMarcus Ware), last year's leader in sacks (Jason Hatcher) and their best playmaker (Sean Lee). Rod Marinelli takes over for Monte Kiffin as the defensive coordinator and will bring subtle changes in coverages, fronts and blitzes, but the core of the 4-3 scheme will remain the same as when that coaching duo was together at Tampa Bay. The Cowboys did not make any splash signings in free agency, but their most important was Henry Melton. If he can come back from a torn anterior cruciate ligament and play the way he did under Marinelli in Chicago, the Cowboys have a chance. Marinelli also plans to lean more on cornerbacks Brandon Carr, Orlando Scandrick and Morris Claiborne in man coverage, but Carr and Claiborne have to play much better in 2014 than they did in 2013. There could be as many as seven new opening day starters on defense this season than in 2013, and it is up to Marinelli to make it work. He had more talent with the Bears when he was running their defense, but the players believe in what he is selling.

Plan of attack: From 2007 through 2012, Jason Garrett called every offensive play. In 2013, Bill Callahan was the playcaller, but he was forced to run Garrett's offense, and there were hiccups. Scott Linehan will be Romo's third playcaller in as many years, and he will have the autonomy Callahan did not have. The Cowboys are not changing schemes, but Linehan has brought on alterations to an offense that struggled on third down in 2013. Linehan leaned toward the pass in his time with the Detroit Lions, but he did have a 1,000-yard rusher in Reggie Bush last season. With the Cowboys, he has a better offensive line, better tight end (Jason Witten) and better running back (DeMarco Murray). The Cowboys aren't about to become a run-first team under Linehan, but they need to run more, especially when they have a lead in order to help end games, protect a defense filled with questions and protect Romo, who is coming off two back surgeries. Because Romo did not take any team or seven-on-seven snaps in the spring, they will need to play a little bit of catch-up in what each other likes and, perhaps more importantly, doesn't like in situational football. The Romo-Linehan relationship might be the most important the Cowboys have. They have to make it work.