NFL 2015: The X-factor for all 32 teams

Robert Mathis – Indianapolis Colts

The Indianapolis Colts are expected to make a push for the Super Bowl, but they are not going anywhere without a pass-rush. The AFC is loaded with top quarterbacks, ranging from Tom Brady and Peyton Manning to Philip Rivers and Ben Roethlisberger. While the Colts certainly have the offensive firepower to keep up with anyone, they will also need to stop the opponent.

With a suspect defense in many areas, Indianapolis must make up that weakness with pressure. Robert Mathis is coming back off a season-ending Achilles injury and looks to be the difference in a few more January wins. Mathis led the league with 19.5 sacks in 2013 before getting suspended for performance-enhancing drugs to start 2014 (and was then injured). Getting Mathis back in his old form could have the Lombardi Trophy residing in Naptown.

Dorial Green-Beckham – Tennessee Titans

The first rookie of our list is Tennessee Titans wide receiver Dorial Green-Beckham. Many believed Green-Beckham was the second-most talented receiver in the class behind Alabama’s Amari Cooper, but fell to the second round because of off-the-field character concerns. General manager Ruston Webster is taking a gamble on the 6-foot-5 youngster, who has all the potential in the world.

Green-Beckham figures to start immediately alongside Kendall Wright, giving fellow rookie Marcus Mariota a massive target to throw at. If Green-Beckham can burst onto the scene such as Mike Evans or Odell Beckham Jr., the Titans stand to make major strides. This offense has lacked real punch since Chris Johnson was a top running back, so getting a premiere player would make all the difference.

Cecil Shorts III – Houston Texans

Last year, the Houston Texans had Andre Johnson and DeAndre Hopkins patrolling outside the numbers, giving Ryan Fitzpatrick two quality options. However, Houston released Johnson for financial reasons, leaving a large hole on an offense already rife with question marks. Texans general manager Rick Smith decided to fortify the position by drafting Jaelen Strong in the third round while adding slot receiver Cecil Shorts in free agency.

Shorts was productive over his four years with the Jacksonville Jaguars. However, the knock has always been durability. The Mount Union product has never played more than 14 games in a season, missing six over the past two years for various ailments. When he’s on the field, Shorts has produced. In 2012, Shorts racked up 979 yards and the following year posted 777, despite some of the worst quarterback play in the NFL. He’ll need to be productive for Houston to move the ball.

Julius Thomas – Jacksonville Jaguars

Few moves in the offseason caused such a ruckus as when the Jacksonville Jaguars signed tight end Julius Thomas to a five-year, $46 million deal. The supporters will point out that Thomas caught 24 touchdown passes over the past two years and is one of the more athletic players in the game. His detractors make sure to notice that Thomas has missed five games over that span and is without an 800-yard season, including a 489-yard campaign in 2014.

Thomas doesn’t need to be Tony Gonzalez, but he must be a reliable pass-catcher and yards-eater for second-year quarterback Blake Bortles. Bortles has promising receivers in Allen Robinson and Marqise Lee, but now he gets a top-notch red zone target. Thomas needs to prove he isn’t a product of Peyton Manning and is capable of double-digit touchdowns elsewhere.

Next: AFC West X-factors