5 Biggest Obstacles Facing Oakland Raiders in 2015

The Oakland Raiders have made a lot of important additions this offseason. On paper, this is a much improved team from the one that finished last season with a 3-13 record.

But as everyone knows, games aren't won on paper. While Oakland added talent at almost every position, it won't mean anything until this rebuilt roster can consistently put together winning performances on game days.

There's a reason why the Raiders had to rebuild their roster. Watching them play last season, it was clear there was no shortage of problems to fix no matter where you looked. This roster was rebuilt this offseason, and these problems are the reasons why.

The key to Oakland finally getting back to its winning ways will be whether this new-and-improved roster is in fact good enough to fix these problems.

Here's a look at the five biggest obstacles Oakland has to overcome this upcoming season to finally get back to its winning ways.

5. Establishing an Effective Passing Game

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Considering how much quarterback Derek Carr had on his plate in his rookie season, he should be given credit for performing as well as he did. But the flashes of potential he showed shouldn't be confused with proof he's established himself as Oakland's franchise quarterback.

While there's a lot to be excited about following Carr's first season, there's also a lot to be concerned about. A primary concern is his paltry 5.46 average yards per completion, which ranked him 33rd in the league.

He was also underwhelming in other categories. He finished the season with a lowly 58.1 completion percentage and a passer rating of 76.6, both of which left him ranked 30th in the NFL.

The responsibility for Oakland's weak passing attack wasn't all on Carr. The Raiders had arguably the weakest receiving corps in the NFL, and the team's rushing attack was non-existent for most of year.

These are no longer excuses. The receiving corps is much stronger thanks to the additions of Amari Cooper and Michael Crabtree and the return from injury of Rod Streater. Oakland also should have a stronger, more reliable backfield thanks to the emergence of Latavius Murray and the pass-catching ability of Roy Helu.

Ultimately, it's the quarterback that will make or break the passing game. Too often in 2014, Carr settled for the dump-off pass. Sometimes this was because no one could get open downfield. But just as often, it was Carr going with the easier, safer pass that was short of a first down.

Carr certainly has the talent. Now, he needs to show it in games. His improvement needs to be significant. His completion percentage needs to improve by 5-6 points, his passer rating needs to improve by at least 10 points, and his yards per attempt average needs to jump up by at least 1.5-2.0 yards.

The Raiders' passing attack needs to be dangerous. If an opportunity is there, the passing game needs to be able to take advantage of it. Otherwise, it'll be another frustratingly ineffective season for the Oakland offense.

4. Finding a Defensive End That Will Get to the Quarterback

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The Oakland front seven has real potential to shock a lot of people this season. With Curtis Lofton, Dan Williams and Justin Ellis manning the middle of the field, this team is going to provide a stiff defense against the run. At outside linebacker, Khalil Mack and Sio Moore are capable of wreaking havoc on opposing offenses on every play.

But there's still uncertainty at defensive end.

One of Oakland's biggest problems on defense last season was giving opposing quarterbacks too much time to work. This was the reason why guys like Geno Smith, Ryan Tannehill and Ryan Fitzpatrick looked like world-beaters when facing the Oakland defense.

Aside from an aging Justin Tuck, the Raiders will enter this season without a proven edge-rusher. Rookies Mario Edwards and Max Valles will get their opportunities, but neither is proven. Aside from them, the team's options are rotational backups like C.J. Wilson and Benson Mayowa.

The hope is that second-round pick Edwards will be able to fill this need. He has the talent, but he didn't prove to be much of a sack artist while at Florida State. According to sports-reference.com, he finished his three-year college career with only eight sacks. In his best season, he only had 3.5 sacks. That doesn't inspire much confidence that he'll be able to consistently get to the quarterback in the NFL.

Tuck isn't the player he used to be, but he still has something left in the tank. Now, Oakland has to find someone to consistently line up opposite of Tuck who can be effective. This is an absolute must.

If the Raiders don't find someone to fill this role, it's going to be another season of average quarterbacks looking like superstars at Oakland's expense. And it'll be even worse against elite quarterbacks.

3. Cornerbacks Proving They Can Hold Their Own

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The Raiders entered the offseason with plenty of needs and tons of cash. The team also had a full slate of draft picks. This made it all the more confusing and frustrating to watch as Oakland did nothing to reinforce the cornerback position.

Oakland showed a lot of confidence in a talented but unproven group of young cornerbacks comprised of D.J. Hayden, T.J. Carrie and Keith McGill. This group doesn't inspire much confidence, but it'll have to do because this is what the team has.

The Oakland front seven is much better than it was last season, and this will help minimize the effectiveness of opposing quarterbacks. But ultimately, it's going to come down to the play of the cornerbacks themselves.

Hayden, Carrie and McGill are going to have to step up and contain receivers like Jordy Nelson, Randall Cobb, Steve Smith and Demaryius Thomas while defending against quarterbacks like Peyton Manning, Aaron Rodgers, Philip Rivers and Joe Flacco.

Nothing in the limited history of these cornerbacks suggests they'll be up to the task. But they're going to have to prove the confidence the organization showed in them is well-founded. If they don't, the Oakland secondary will be methodically picked apart often.

2. Finding a Reliable Running Back

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For all the struggles the Oakland offense went through last season, by far the team's worst overall performance on either side of the ball came from the running backs.

For most of the season, the rushing attack just wasn't there. Darren McFadden had a bad season, and Maurice Jones-Drew's was even worse. The Oakland passing attack struggled, and sometimes the blocking up front wasn't great. But ultimately, it came down to the running backs' inability to make anything happen.

Oakland has completely revamped its backfield. Latavius Murray is the early leader to win the starting spot, but Trent Richardson, Roy Helu and Marcel Reece will also get their opportunities to make plays.

The Raiders certainly have options at running back, and the offensive line is much stronger with the addition of center Rodney Hudson. It's now up to the running backs themselves to produce.

The Oakland offense overall is a lot more talented than it was a season ago, and that includes both the players on the field and the coaches calling the plays. Carr will be better this season, and the team has wide receivers and tight ends that can go out and make plays.

But none of that will matter if the team can't run the ball. While the offense is much better overall, the success of the unit is going to come down to whether it can move the ball on the ground.

1. Ending the Tradition of Losing

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The great Vince Lombardi once said, "Winning is a habit." The opposite of that is also true. Unfortunately for the Raiders, losing hasn't just become a habit. It's become a tradition.

After so many years filled with so many defeats, losing has become easy in Oakland. Instead of truly hurting, each defeat has now become just another loss. Losing streaks are expected. Finishing with a winning record, much less actually making the playoffs, has become more and more of a foreign concept.

The biggest obstacle Oakland will have to overcome in 2015 is finally putting an end to this losing tradition. It'll be even tougher because overcoming this won't be a matter of statistics. It'll be a matter of the heart and the mind. From the players to the coaches, everyone has to buy into the idea that winning will now be expected, not just a pleasant surprise.

The current version of the Raiders is without a doubt the best version in years. From top to bottom, it's arguably the most solid version of the team in over a decade. But none of that means anything if the team doesn't start expecting to win instead of just hoping for it.

The Raiders have the players and the coaching staff to win now. Actually believing they can will be the most difficult challenge of all.

Unless otherwise noted, all stats taken from Pro-Football-Reference.com and NFL.com.

What do you think is Oakland's biggest obstacle this upcoming season? Share your thoughts in the comments section below and on Twitter @BrianJ_Flores.