Who were the 2013 Steelers? The 2-6 team from the first half of the season, or the team that finished 6-2 over their final eight games?

The Pittsburgh Steelers ended the 2013 season one Ryan Succop made field goal away from making the playoffs. One correct call by the NFL refereeing crew in San Diego could have given the Steelers a trip to Cincinnati in the Wild Card Round of the playoffs.

Instead, it wasn't to be this season for the Steelers, and they only have themselves to blame. As has been the case in recent years under Mike Tomlin, the Steelers played down to the level of their competition throughout the year, getting beat by inferior teams like Oakland, Minnesota and Tennessee.

The Steelers have now finished 8-8 and missed the playoffs in two straight seasons. Since losing Tim Tebow's Denver Broncos, Pittsburgh has slowly just become another team on the schedule.

The lack of success in 2013 can be attributed to some major injuries including Pro Bowl center Maurkice Pouncey and starting linebacker Larry Foote missing nearly the entire season. Aside from injuries, the Steelers played their way into an 0-4 hole to start the 2013 season with simple erratic play.

Quarterback Ben Roethlisberger turned the ball over far too often early in the year, and without rookie running back Le'Veon Bell or tight end Heath Miller in the lineup, the Steelers running game ranked 30th in the NFL over the first month of the season according to our Adjusted Rushing Net Expected Points (NEP) metric.

The offense certainly didn't carry their weight early in the season, but the defense was historically poor during the first eight games of the year. During that time, the Steelers Adjusted Defensive NEP was 53.82. This means that an average team would have allowed 54 fewer points than the Steelers have if put in a similar situation.

Despite being 2-6 at the halfway mark of the season, the Steelers didn't make excuses for injuries and adversity. Head coach Mike Tomlin always preaches, "the standard is the standard". The second half of the season spoke volumes about the character of this team and franchise. The Steelers didn't quit on the season, finishing the second half of the year 6-2. According to our Adjusted DNEP metric, the Steelers defense improved from the poor midseason rating to finish the season with a 34.74 mark, which was good enough for 17th in the NFL.

Let's take a deeper look at what worked and what didn't work for the Steelers in 2013.

The Good

The number that jumped out to me in reviewing the Steelers 2013 season was seven. The Steelers offensive line allowed only seven sacks over the final seven games on quarterback Ben Roethlisberger, who of course wears the number seven. If you have watched the Steelers over the past four or five seasons, you know very well that seven sacks in a game or two was not out of the question for this team.

In my opinion, the main reason the Steelers offensive line (patchwork line, to be clear) was able to keep their quarterback upright was a change in offensive philosophy. Offensive coordinator Todd Haley finally took the training wheels off his two-time Super Bowl winning quarterback and let him run an up tempo, no-huddle style of offense.

During the second half of the season, Roethlisberger was able to get rid of the ball quickly and on time in an offense with plenty of speed at the wide receiver position, as well as effective pass-catching weapons like Heath Miller and Le'Veon Bell. Running the up-tempo offense allowed the Steelers to improve in offensive efficiency greatly over the second half of the season.

The Steelers finished the year ranked eighth in the NFL in passing offense, compared to 16th at the midway point of the season. The improvement was drastic and will continue to trend upward with the return of a healthy Pouncey and newly hired offensive line coach Mike Munchak, now in the fold for 2014.

No doubt the star of the 2013 season for the Steelers was wide receiver Antonio Brown. Number 84 became the first wide receiver in NFL history to catch at least five passes and record 50 yards in all 16 games of the NFL season.

According to our Reception Net Expected Points metric, Brown ranked seventh in the NFL in 2013 with a rating of 120.20. He also ranked second in the NFL with 110 receptions, and second with 1,499 yards. Brown had a spectacular season, and it's obvious that the Steelers let the right wide receiver walk in free agency when they decided to pay Brown instead of Miami's Mike Wallace.

Despite his low yards per carry average, rookie running back Le'Veon Bell was a bright spot for the Steelers offense as well. Bell brought stability at the running back position that the Steelers have lacked since the days of Jerome Bettis and Willie Parker. Bell was a model of consistency in the fantasy world making him a dynasty target this offseason and a high-end RB2, at least, heading into 2014.

However, it should be noted that he didn't grade out well according to some of our metrics. The make-shift offensive line and inconsistencies of being a rookie runner placed Bell 24th in Rushing NEP among runners with at least 150 carries in 2013. However, his Total NEP (combining rushing and receiving) placed him 14th among all running backs, one spot behind Adrian Peterson.

Bell racked up 860 rushing yards to go along with 399 receiving yards on 45 receptions in just 13 games played in his rookie campaign. With 1,259 total yards, Bell broke Franco Harris' record from 1972 for Steelers rookie all-purpose yards. His ability as a pass catcher gives him added value in PPR leagues moving forward. Look for Bell to catch 55-60 passes in 2014.

On defense, several things stood out from the 2013 campaign. First, Troy Polamalu returned to Pro Bowl form in 2013, largely due to his ability to play all 16 games for the Steelers. Polamalu forced seven turnovers this season and played all over the field including linebacker in some nickel and dime packages. He is due $10 million dollars in 2014 though, the final year of his contract, and I believe the Steelers will find a way to retain him for at least one more season.

Outside linebacker Jason Worilds may have been the biggest surprise on the defensive side of the ball though. With the first-round selection of Jarvis Jones and firmly entrenched starter LaMarr Woodley in place, Worilds seemed to be the odd man out at outside linebacker. Worilds responded in a big way, leading the Steelers with eight sacks as well as forcing two fumbles.

Jason Worilds was a force all season long with consistent pressure on the quarterback. The Steelers need a strong outside pass rush in their 3-4 scheme, and it will be interesting to see how the Steelers value Worilds as an impending free agent. With LaMarr Woodley's down play in recent years and inability to stay on the field due to injuries, I believe the Steelers front office should prioritize resigning Worilds.

Cameron Heyward emerged as a true force on the defensive line for the Steelers in 2013, too. After replacing Ziggy Hood in the starting lineup in Week 4, Heyward racked up 35 tackles, 5 sacks and 7 passes defended. It looks like the Steelers hit on one of their recent first-round picks after a string of questionable high draft picks during the Tomlin era.

Sixth-round pick Vince Williams stepped in for injured Larry Foote, starting 11 games this season and flashed some ability at the middle linebacker position. Williams still has a lot to learn but could be a solid starter for years to come at a bargain price.

The Bad

Coming into the season, the expectations were high for the Steelers. Many pundits picked them to re-emerge as the top dog in the AFC North. However, many of the same issues haunted the Steelers in 2013: the inability to create turnovers resulted in the Steelers being the last team in the NFL to force a turnover this season

The offense struggled early in the year to find any sort of rhythm and eventually turned to a pass-heavy attack to move the football. The offense will need more balance in 2014 to reach the levels of the elite offenses in the game today. Le'Veon Bell certainly created a spark in the running game upon his return from injury, but the numbers don't lie; the Steelers ranked 29th in the NFL this year according to our Adjusted Rushing NEP metric.

The Steelers are known for running the football and stopping the run. They have been most successful over the years when they are able to do control the clock and apply pressure with the zone blitzing defense. This season, however, the Steelers failed in both categories and must address these issues moving into the 2014 season.

What Should They Do?

The Pittsburgh Steelers have several issues to address in the 2014 offseason. The first is that the team must examine the long and important list of free agents. The Steelers have begun a young movement, but are still one of the oldest rosters in the NFL on defense.

Veteran staples Brett Keisel and Ryan Clark are both impending free agents. Right now it doesn't appear that the Steelers have better replacements on the roster. What will the Steelers do with the veteran free agents? Although there may be some growing pains, I believe it's time to move on and allow young players to fill those roles.

Analyzing the roster shows some real gaps in the secondary and on the defensive line. At cornerback, the Steelers have 33-year-old Ike Taylor signed for one more season, but is he really worth keeping around at his $7 million dollar cap number? Aside from Cortez Allen, the Steelers have no long-term solution at cornerback.

My initial analysis of the 2014 draft board puts talented cornerback prospects Justin Gilbert of Oklahoma State and Darqueze Dennard of Michigan State in range for the Steelers to draft at 15. I firmly believe the Steelers will consider drafting cornerback in the first round for the first time since they selected Chad Scott in 1997.

On the defensive line, both Brett Keisel and Ziggy Hood are free agents. A 2009 first-round pick, Hood has not panned out as the Steelers had hoped. He may return on a team-friendly deal, but the Steelers need to find a way to address the defensive end position in the draft.

On offense, wide receiver is a huge question mark this offseason. Behind Antonio Brown, second and third leading receivers Emmanuel Sanders and Jerricho Cotchery are both free agents. I could see the Steelers resigning Cotchery for a veteran minimum contract, but as with Mike Wallace and others, I believe the Steelers will allow Sanders to walk in free agency.

The next man in line is 2013 third-round draft pick Markus Wheaton. Wheaton had an injury-plagued rookie season and was never able to jump veteran Cotchery on the depth chart. Wheaton has extremely impressive college tape and I believe he will be a factor in 2014. Wheaton should have a chance to start opposite Antonio Brown. If you play in dynasty leagues, I would certainly keep my eye on Wheaton this summer.

One of the most important things the Steelers need to check off the to-do list is extend franchise quarterback Ben Roethlisberger's contract. Some have criticized Roethlisberger over the past two seasons, but it's no secret that the Steelers go as Big Ben goes. Among starting quarterbacks who played more than 80% of their teams snaps in 2013, Roethlisberger guided the eighth-ranked passing offense and ranked seventh in the NFL according to our Passing Net Expected Points metric.