The Steelers find themselves in perennially interesting times. This isn't the most successful run of the storied franchise's history, with the controversial wild-card win over the Bengals serving as their first playoff victory since beating a Mark Sanchez-led Jets team in the 2010 AFC Championship Game. But they've consistently been in the swing of things in the AFC. This season marked their second consecutive postseason berth, and even though the start of that streak came after a two-year drought, the Steelers were the last team eliminated from contention in the AFC in both of those seasons. It's hard to remember the last time the Steelers were irrelevant.

The good news is that Pittsburgh should continue to be an above-average football team. You can make a case that the Steelers were held back in 2015 in ways that are unlikely to repeat themselves in 2016, that it was the dawn of a much-improved defense to go along with one of the league's most devastating offensive attacks. And yet, at the same time, the Steelers may also find themselves subject to the same concerns about depth and roster construction, which might have capped their ceiling in both 2014 and 2015. Here's what Steelers fans should both love and fear about Pittsburgh's future.

The good

You can make a realistic case that the 2015 Steelers were actually a more impressive team than the 2014 edition. Their record dropped from 11-5 to 10-6, and they fell from the catbird seat in the AFC North to the No. 6 seed, but on a play-by-play basis, the Steelers actually played better. They outscored their opponents by 104 points in 2015, a rise from their 68-point margin the previous year. The Pythagorean expectation suggests that that's a difference of almost exactly one win over 16 games (10.6 wins vs. 9.6 wins).

A quick survey of advanced metrics also pegs the Steelers as an improved team. They rose from a DVOA of 12.1 percent in 2014 to 21.3 percent this year, even if that only meant a one-rank improvement. Their FPI improved from plus-2.4 to plus-7.2, leaping them from 13th in the standings to fourth. Pro-Football Reference's Simple Rating System bumped them from 12th to fifth, just ahead of the 15-1 Panthers. Their record might have declined, but remember that Pittsburgh was two Josh Scobee misses in Week 4 away from finishing with the same 11-5 mark they posted a year ago. The thousands of data points in a play-by-play metric are more meaningful and predicative in judging how a team performed than the 16 data points in a win-loss record, even if the latter is what determines success.

Beyond the numbers, what makes Pittsburgh's season so impressive is that they were able to get slightly better while dealing with a horrific stack of injuries, especially on the offensive side of the football. The Steelers were remarkably lucky with injuries in 2014, with their 11 offensive starters missing a total of just seven games due to injury. That obviously was not the case this season, starting with center Maurkice Pouncey, who missed the entire season after fracturing his fibula in a preseason game against the Packers.

If you include the suspensions incurred by Le'Veon Bell and Martavis Bryant, Pittsburgh's 11 expected offensive starters heading into training camp missed a total of 46 games this season. Just four of those expected starters made it through all 16 games. And that doesn't include the injury that might have cost the Steelers their playoff run, a concussion suffered by Antonio Brown late in the playoff victory over the Bengals. Brown was one of those four players to make it into all 16 games. It's difficult to imagine the Steelers being so injury-hit in 2016, even if they are also unlikely to be as healthy as they were a year ago.

The Steelers were hit by a rash of injuries on offense, including a torn MCL from RB Le'Veon Bell. Jared Wickerham/Getty Images

With the offense dropping off ever so slightly -- falling from a 22.2 percent DVOA in 2014 to 17.3 percent in 2015 -- the improvement was driven by the Pittsburgh defense, which was markedly better after bottoming out last season. The Steelers were 30th in defensive DVOA in 2014, which led to the departure of a pair of franchise icons, defensive coordinator Dick LeBeau and safety Troy Polamalu. Unsurprisingly, even amid the upheaval, the Steelers chose to trust their organizational philosophy and promoted longtime coordinator-in-waiting Keith Butler to the top defensive job.

The moves paid dividends. The Steelers were not exactly the Steel Curtain of old, but they were a much better unit, making the biggest leap of any defense in DVOA, from 30th to 11th this season. Led by burgeoning stars Cameron Heyward and Ryan Shazier, the Steelers featured the league's fifth-ranked run defense.

The defensive improvement came about thanks to two positive indicators, both of which may be difficult to sustain in 2016. One, coincidentally, was health. The 2015 Steelers' defense wasn't quite as healthy as the 2014 Steelers' offense, but the defense certainly benefited from a relatively injury-free campaign. Pittsburgh's 11 expected starters on defense missed a combined 22 games, but 15 of those were tied up in starting cornerback Cortez Allen, who had been benched after a disastrous 2014 campaign and might not have won a starting job if he had been healthy enough to play. Pittsburgh's other defensive starters missed a combined seven games.

The other was a sudden spike in Pittsburgh's ability to induce takeaways, a skill which had been missing for years. As easy as it is to think back to the peak of the Polamalu era and imagine the future Hall of Famer scything through the secondary for picks, the Steelers have been below-average in terms of forcing takeaways for some time now. After ranking fifth in terms of percentage of opposing possessions ending in takeaways in 2010, LeBeau's defense was 30th in the same stat in 2011, 25th in 2012, 24th in 2013, and 23rd in 2014.

In 2015, though, Butler's defense started coming up with big plays. The Steelers ended 14.8 percent of opposing possessions with a takeaway, the seventh-best rate in football. They weren't a great defense when they weren't snatching away the ball, ranking just 26th in terms of forcing three-and-outs, but some -- not all, but some -- of that was driven by the fact that they were swapping three-and-outs for changes of possession. That's a trade any team will make.

The proof was in the win-loss pudding for the Steelers. When their defense forced three turnovers or more in 2015, Pittsburgh went 7-0. In the 10 games where they forced two turnovers or less, the Steelers were 4-7. That seems like a tautology -- of course teams are going to play better when they force more takeaways -- but even the rest of the NFL only went 72-20 (.782) when they forced three or more takeaways in a game this season.

Can they keep that up? It's hard to say. Turnover spikes like the one the Steelers just executed tend to be difficult to sustain, especially when it comes with similar personnel. Take the 2014 Texans: After ranking dead last in takeaways per drive in 2013, Houston hired Romeo Crennel and made some minor shifts on the defensive side of the football, but otherwise kept the core of its defense together. Facing a remarkably turnover-friendly schedule of quarterbacks, the Texans improved all the way to third in the league in takeaway percentage. In 2015, despite retaining their defensive stars, Houston's defense dropped back to 23rd in turnover rate.

Houston only dropped from sixth in defensive DVOA to eighth with that decline, in part because its stars -- namely J.J. Watt -- still played at a high level even without the takeaways. The Steelers have to hope their defenders can do the same thing. The good news is that quite a few of their upper-echelon players are young. Heyward is 26. Shazier is 24. The same is true on the offensive side of the ball, where Brown is 27 and fellow wideout Bryant is 24. Mauling guard David DeCastro is 26, as is Pouncey. Bell, somehow, is only 23. If those players can stay healthy, there's little reason to think they will play worse in the years to come.

The bad

That's a core of young talent that just about any team in the league would kill to have, especially alongside an excellent veteran quarterback like Ben Roethlisberger. The problem is that the Steelers have struggled to surround that young talent with the sort of solid depth that would raise Pittsburgh's ceiling to that of a perennial Super Bowl contender. That's been primarily related to the salary cap, and it's a problem which is going to impact the Steelers for the foreseeable future.

The Steelers didn't feel the pinch of the salary cap quite as tightly in 2014, thanks to the remarkable health among their offensive talent. It only really hurt them in the secondary, where replacement-level players like Brice McCain and William Gay were forced to play meaningful roles at corner during the team's playoff loss to the Ravens.

Michael Vick started three games while Ben Roethlisberger was out with an injury. Timothy T. Ludwig/USA TODAY Sports

This year, with injuries up on the offensive side of the ball, Pittsburgh's inability to plug holes because of cap concerns became a bigger issue. Despite having one of the league's most injury-prone quarterbacks in Roethlisberger, the Steelers had to save money on backups and paid Bruce Gradkowski and Michael Vick a combined $2.4 million, far less than even the Chase Daniels of the world get by themselves. They lacked badly-needed offensive line depth and were out of luck once Pouncey and left tackle Kelvin Beachum went down with season-ending injuries, leaving Pittsburgh with journeyman Cody Wallace and fascinating project Alejandro Villanueva in key roles for most of the season.

Defensively, while the health of Pittsburgh's starters masked the need for much depth, the Steelers weren't able to add much at all to their struggling secondary. Gay stuck around and started all 16 games across from Antwon Blake, who the Steelers signed off of Jacksonville's practice squad. Thirty-three-year-old Will Allen, the third-oldest starting safety in the league, beat out Shamarko Thomas for a starting gig. It's hard to think of a team that got by with less talent at defensive back than the Steelers in 2015. Pittsburgh finished the season with only about $5 million in cap space, so it wasn't about to go out and sign Byron Maxwell (and that would have been a bad thing), but the Steelers couldn't even cycle in a midtier free agent like Buster Skrine to compete for steady work.

The one move Pittsburgh did make didn't work out: they sent a fifth-round pick to the Eagles for slot cornerback Brandon Boykin, who was entering the final year of this deal and out-of-favor with Chip Kelly. Boykin never found his role, playing just 24.7 percent of snaps on his way to unrestricted free agency this offseason. The Steelers also spent a sixth-round pick on Scobee, who went 6-for-10 and cost Pittsburgh the game against the Ravens before being released. It's easy to write off fifth- and sixth-round picks as selections which are unlikely to return much value, but remember: The Steelers found Brown with a sixth-round pick in 2010. Picks are precious.

Look at Pittsburgh's cap page for 2015 and you'll see where the problems are this year. Pittsburgh owed $19.5 million in dead money to players who are no longer on the roster, including LaMarr Woodley ($8.6 million), Polamalu ($4.5 million), and Scobee ($2.5 million). The good news is that all of that money slides off of Pittsburgh's cap this offseason, and the Steelers have less than $800,000 in dead money assigned to their cap in 2016.

The bad news? All of that money has already being gobbled up by raises for Pittsburgh's star players. The price of everyone is going up next year:

Player 2015 2016 Difference Ben Roethlisberger $17,245,000 $23,950,000 $6,705,000 Lawrence Timmons $9,251,250 $15,131,250 $5,880,000 Antonio Brown $7,120,833 $12,370,833 $5,250,000 Cameron Heyward $6,400,000 $10,400,000 $4,000,000 Maurkice Pouncey $4,296,000 $10,551,000 $6,255,000 David DeCastro $2,486,240 $8,070,000 $5,583,760 Total Cap Change $46,799,323 $80,473,083 $33,673,760

There are various reasons why the numbers are shifting upward. Roethlisberger and Heyward signed contract extensions. DeCastro is entering the fifth-year option of his rookie deal, which guarantees him a massive (and deserved) raise. Brown's remarkably team-friendly contract, one of the best deals in all of football for years, has been restructured and shifted to the point where it's now simply a very good contract. Last year, the Steelers were paying Brown like he was Golden Tate; they're now paying him like he's Dez Bryant.

It's the Timmons deal that signifies how Pittsburgh mismanages its cap. While Timmons is an above-average inside linebacker, the Steelers have been forced to restructure his contract twice in three years to create much-needed cap space. Now, in the final year of the 29-year-old Timmons's contract, they're stuck. His $15.1 million cap hit is the highest for any inside linebacker in football by a comfortable margin, and it doesn't reflect his production. The Steelers can give Timmons an extension, but that'll be a deal negotiated with Timmons possessing all the leverage and kick the problem down the line, which is the exact sort of deal you don't want to do. They've already had to restructure the Pouncey contract, and it wouldn't be a surprise to see them restructure Roethlisberger's deal while the ink is still drying to clear out more space.

That's a necessity, because the Steelers are losing all kinds of contributors and have just $10 million in cap space before re-signing any of them. No fewer than six starters are hitting unrestricted free agency this offseason, and Pittsburgh can't afford to lose them all. That includes three members of that secondary in Blake, Gay and Will Allen; they aren't exactly stars by any means, but the only players in line to replace them are Cortez Allen and rookie second-rounder Senquez Golson, who combined to play one game in 2015 thanks to injuries.

More distressingly, it includes a pair of starters along the offensive line in Beachum and Ramon Foster. The offensive line was a dominant asset for Pittsburgh in 2014; losing its left side with no heir apparent at either position would be a critical blow. In a way, the Steelers might have gotten lucky that Beachum tore his ACL this year, if only because it might reduce his market value as he hits free agency and make it possible for the Steelers to re-sign their 2012 seventh-round pick. Nose tackle Steve McLendon rounds out the group, and that's without thinking about Boykin, fullback Will Johnson, or either of their veteran backup quarterbacks. The Steelers also need to prepare extensions for Bell and DeCastro, each of whom would become unrestricted free agents in 2017, and start working on a mammoth deal for Brown, who would hit the market in 2018.

And so, the Steelers will have to dip back into the piggy bank and create more space. They can save $4 million by cutting Heath Miller, $1.8 million by releasing Shaun Suisham and $4.4 million by designating Cortez Allen as a post-June 1 release. That also leaves them without starters at three positions. The Steelers are perpetually pushing their cap problems into the future while doing whatever it takes to make rent today. As envious as teams should be about their young talent, and as impressive as they've been in 2014 and 2015, that lack of depth and inability to fill out the roster with competent contributors may be what costs the Steelers their chance at winning a Super Bowl with this core of players.