Top Stories Over the next month or so, however, the Cardinals will call University of Phoenix Stadium home as they go through the 2016 version of their annual training camp.What should you be looking for? Here are five things worth watching.The battle at centerFrom 2008 to 2014, Lyle Sendlein was the man in the middle for the Arizona Cardinals. It seemed like his tenure with the team was coming to an end last year, but then the team signed him during training camp and he went on to win — and hold onto — the job. However, Sendlein is once again not on the roster, meaning veteran A.Q. Shipley is set to battle with rookie Evan Boehm and reserve lineman Earl Watford for the starting job.Who will win it?Shipley certainly seems to have the advantage, as he has both experience and a bit of a track record of success. That said, he was the favorite going into camp last year and ended up losing the job, and if Boehm picks up the offense quickly, he could make a push for the role. Even Watford, who has the versatility to play all over the the line, put his name into the mix with a strong offseason.Can D.J. Humphries hold down RT?The 24th overall pick in the 2015 draft, Humphries was inactive for every single one of the team’s games during his rookie season. As the story goes, he was not ready to play early on, earning the nickname “Knee Deep” in training camp because…well…he required interesting forms of motivation. The tone surrounding Humphries began to change around midseason, though, and by the end of the year, the coaches said they would have complete confidence in the youngster if he was needed late in the season. It seems like just yesterday the Arizona Cardinals were playing for the right to represent the NFC in Super Bowl 50.What happened that night in Carolina is best left forgotten.While the entire offseason has been dedicated to trying to improve a team that won 13 games and reached the NFC Championship Game, the fruits of the organization’s labor cannot really be revealed until the players take the field and the games start to count. He wasn’t needed then, though. He is now.Humphries is expected to take over as the team’s right tackle, replacing Bobby Massie after the latter player signed a free agent contract with the Chicago Bears. Is the former Florida Gator ready? By all accounts he had a fairly strong offseason of work, and a coaching staff that is never afraid to call players out spoke rather glowingly of his progress. Still, saying he’s taken steps forward is different than seeing him take those steps, so it will be interesting watching him this camp to see just how far he has come. If he is ready to start, the offensive line will be that much better. If he’s not, well, the Cardinals hope that isn’t the case.Who plays opposite Patrick Peterson?In Patrick Peterson, the Cardinals have arguably the best cover man in all of football. Opposite him, however, is a big question mark.Gone is Jerraud Powers, who filled the role last season but was allowed to leave as a free agent. In his place is a group of players that includes Justin Bethel, Brandon Williams, Harlan Miller and Mike Jenkins, among others.Bethel is the presumed favorite, especially after he signed a three-year, $15 million contract last December. However, he struggled down the stretch and in the playoffs before undergoing offseason surgery on his foot, and while his absence during the team’s OTAs and mini-camps did not cost him his job, the longer he is out (he’s beginning camp on the PUP list), the more opportunities someone else will have to close the gap. Derrick Hall satisfied with D-backs’ buying and selling Grace expects Greinke trade to have emotional impact Former Cardinals kicker Phil Dawson retires Will it be one of the rookies? Could it be Jenkins, a two-time Pro Bowler? Or will another challenger emerge? No doubt whoever it is that gets the job will see the ball come their way often during the season, as most quarterbacks are reticent to throw the ball near No. 21.Return of the BadgerLast season, Tyrann Mathieu proved to be one of the most important and dynamic players on Arizona’s defense, playing a type of defense the league has rarely seen. The third-year pro was listed as a safety, but played plenty of cornerback and was also used to pressure the quarterback and in run support. He emerged as a Defensive Player of the Year candidate and, though he missed two games, finished tied for the team lead in interceptions.Unfortunately, he tore up his knee in Week 15, and is once again working his way back to the field.Mathieu’s recovery this offseason has been closely monitored, as every new step in his rehab has seemingly been documented and celebrated. And though he is beginning camp on the PUP list, Mathieu himself noted how he has no plans to be inactive for very long. Of course, just because a player is confident he will be back on the field soon does not mean he will be, but the quicker Mathieu can get back to being his playmaking self, the better the Cardinals will be. The 5: Takeaways from the Coyotes’ introduction of Alex Meruelo Comments Share Arizona Cardinals head coach Bruce Arians instructs his players during an NFL football training camp practice Monday, Aug. 3, 2015, in Glendale, Ariz. (AP Photo/Ross D. Franklin) Oh, and it would not be a shock to see a contract extension come in for the defensive back at some point during camp, though the Cardinals may want to see him back on the field before formally committing some big-time money to the 2013 third-round pick.Depth is great, but too much depth is…The Cardinals have great depth at receiver and running back, but the one area where their cup really overfloweth is along the defensive line.Robert Nkemdiche is a lock to make the roster, as are Calais Campbell, Rodney Gunter and probably Corey Peters. Xavier Williams has proven capable, too, as have Josh Mauro and Ed Stinson. Red Bryant filled in admirably down the stretch last season and provides a steady veteran presence (as well as a large body), and there is also the rehabbing Rucker who, when healthy, has been one of the team’s better options.That’s nine players and, while no one knows just how many defensive linemen the team plans on keeping this season, there were seven on the active roster by the end of 2015. You don’t need to be a mathematician to realize that some talented players are fighting for a job.