As it turns out, the Seahawks’ 2015 season was an almost exact replica of the 2012 season — from the uneven start to the disastrous postseason finish.

So, if the cycle continues, the Seahawks will be lifting the Lombardi Trophy again one year from now.

Consider the similar paths of the 2012 and 2015 seasons:

**The Seahawks rallied from a 4-4 start to make the playoffs, evolving a paltry offense into a formidable one, and a defense that was terrible in save situations (i.e., protecting leads in the fourth quarter).

**They rallied to win their wild-card game and then got off to a horrendous start in their 10 a.m. divisional game before Russell Wilson led a big second-half rally that fell just short.

**This failure was followed by an immediate excitement about what the future holds, everyone knowing this team is still talented enough to compete for at least a few more seasons.

The big difference: This is not a fresh, young, up-and-coming team like it was in 2012. It is a two-time Super Bowl squad that failed to live up to the high expectations it has set and now needs to partially revitalize itself if it wants to duplicate the 2012-13 cycle.

Seattle’s bumpy 2015 season actually started in last year’s postseason as most of the LOB was banged up — Earl Thomas (surgically repaired shoulder) and Jeremy Lane (recovery from a broken wrist and torn ACL) were especially affected well into the 2015 season.

Contract issues were a constant theme all the way through the first month of the season. Marshawn Lynch got a new deal not long after the Super Bowl, and extensions for Wilson and Bobby Wagner were done as camp started. But Kam Chancellor, Michael Bennett and Bruce Irvin all expressed dissatisfaction with their deals during the offseason. Chancellor sat out the first two games and then played a very average season (forget the “reputation” Pro Bowl).

The defense clearly was not ready to go when the season started, and it showed as they blew several fourth-quarter leads through the first half of the season. It was so bad that they ended up dumping Cary Williams in early December, once Lane returned.

On offense, the coaches made the error of going with a neophyte at center, which wreaked havoc for Wilson through the first half of the season. The switch to Patrick Lewis — among other tweaks — seemed to fix things as the Hawks turned it on in the final seven games. But the line fell flat again in the playoffs, hopefully proving once and for all to Pete Carroll and John Schneider that they need to do more to improve that unit.

Along the way, the Seahawks lost Lynch, Thomas Rawls and Jimmy Graham to injuries — causing more churn to an offense that already was having trouble getting going.

In the end, the Seahawks just never got their heads on straight in 2015. They were easily spooked. Now Carroll and Schneider are going to have to change up the roster a little bit to fix personnel and attitude issues.

That means we will see the departure of some of the core players who were part of the 2012-14 journey. This offseason will be a little different than 2013, when the Seahawks added to their young nucleus, bringing on key defenders Bennett, Cliff Avril and Tony McDaniel and also making a bold, ill-advised move to add Percy Harvin. The first three guys helped them march to the first Super Bowl title in Seattle history.

This year, the Seahawks need to do more than just tweak their roster. Lynch and Irvin likely played their last game for the Seahawks in Carolina. Other key figures who might be headed out include Chancellor, Russell Okung, J.R. Sweezy, Brandon Mebane, Ahtyba Rubin, Jermaine Kearse and Lane. And Bennett’s contract clearly will have to be addressed — unless the Seahawks want to face the same headache Chancellor created (which is why the Hawks need to trade the safety).

Schneider had his hands full in 2015 and will again this year. Beyond addressing the futures of Lynch and Chancellor and adjusting Bennett’s deal, the general manager needs to build an offensive line and secure a couple of defensive tackles — whether it’s re-signing Mebane and/or Rubin and/or adding a veteran. He also needs to see about Lane, RFA DeShawn Shead, Kearse and Jon Ryan.

The Seahawks already have permanent or temporary replacements for Lynch (Thomas Rawls), Irvin (Kevin Pierre-Louis/Frank Clark), Chancellor (Kelcie McCray), Sweezy (Mark Glowinski) and Kearse (Tyler Lockett). They could use the draft to replace Okung (if they can’t trade for Joe Thomas). They also have plenty of options for the No. 2 corner position. And they could pick up a new punter (one without a broken nose) if they really needed to.

The one guy they cannot — or should not — replace is Bennett. And defensive tackle is the one position for which they definitely need to sign some guys (Mebane, Rubin or free agents).

It could end up being a lot of turnover (as many as 10 starters) or very little (as few as four), but Schneider will figure it out and fill in the blanks — as always.

Fortunately, the core of the team is still in place and primed to compete for Super Bowls for at least the next couple of seasons.

“I think people get confused sometimes,” Richard Sherman said, “like our quarterback is 38. We have a young core. I think people have been astounded by what we have been able to do in our young years. But we are far from done. Guys are just entering their prime, and we are going to be special for a long time.’’

It all starts up again next season, when the Seahawks will hope to follow the path of the 2013 club and win the Super Bowl again.