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The San Francisco 49ers featured the NFL's most complete roster during the 2019 campaign. It wasn't enough.

Despite the league's best defensive front, its No. 1 passing defense, an elite rushing attack and the game's best tight end and fullback, the 49ers failed to counter Patrick Mahomes and the Kansas City Chiefs during a 31-20 loss in Super Bowl LIV at Hard Rock Stadium in Miami Gardens, Florida.

Here's the real problem for San Francisco: The 49ers may have ruined their best opportunity for a Super Bowl victory because the squad they field next year will be vastly different based on the amount of turnover the organization should expect. Plus, they should simultaneously be starting to wonder about Kyle Shanahan's status leading the squad.

"It's a real close team," Shanahan told reporters after the game. "Everyone is disappointed. They should be. I wouldn't expect anything different because guys put their hearts into this season and came up one game short. ... This is going to take a little bit of time to get over, but we'll be alright."

The coach's first and last points resonate for different reasons.

The 49ers now face a daunting offseason with multiple key contributors set to enter free agency. There's no guarantee this group with be alright in 2020 and beyond.

Turnover is a fact of NFL life since free agency took root. Vultures (i.e. other franchises) are often ready to swoop in and pick at the league's most successful organizations. The 49ers don't have too much financial wiggle room with 17 free agents (unrestricted and restricted) to address.

According to Spotrac, San Francisco has only $21.029 million in projected salary-cap space.

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Before general manager John Lynch can even turn his attention to free agency, he has a major contract to negotiate with all-world tight end George Kittle. The 49ers can't allow the first-team All-Pro to enter the final season of his rookie deal.

According to NFL Network's Mike Garafolo, negotiations will happen relatively soon, and the 49ers will make the extension a "priority." Garafolo expects Kittle's next contract to push the boundaries of $13 million annually and make him the league's highest-paid tight end.

Once Kittle's new deal is complete, San Francisco will have very little financial flexibility to retain some of its top performers. The potential departure of four particular free agents could have a significant effect on different phases of the game.

So much has been made about the five first-round picks the 49ers feature along their defensive front. The number will likely be reduced by one next season.

Arik Armstead's retention isn't feasible, especially with so little workable salary-cap space. He will be one of the league's premier free agents after a breakthrough campaign. The 26-year-old defensive lineman registered a career-high 10 sacks this season and developed into a legitimate disruptive presence. He also racked up 62 regular-season pressures, per Niners Nation's Akash Anavarathan.

The pending free agent's status will likely be tied to his long-time teammate, DeForest Buckner. Like Kittle, Buckner will enter the final year of his rookie deal if something isn't done this offseason. He has been a more consistent performer than Armstead throughout their careers and will likely take priority.

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Whereas, Armstead's market will be flush with suitors when the new league year begins. Other franchises are always willing to back up the Brink's truck for proven pass-rushers in their primes.

Safety Jimmie Ward is another first-round pick ready to maximize his next payday. The 2014 30th overall pick took years to establish himself. He struggled through injuries while playing multiple positions before finally finding a home at free safety in Robert Saleh's defensive scheme.

How good was Ward along the back line of the 49ers defense? According to Pro Football Focus, he had an 80 percent forced incompletion percentage when lined up at free safety prior to Sunday's Super Bowl.

Ward's skill set as the last-line defender and his overall versatility can't and won't be easily replaced if the 28-year-old defensive back decides to cash in elsewhere.

Another vital rotational piece could leave in Sheldon Day. The 25-year-old didn't receive the same attention as the previously mentioned first-round defensive linemen. Armstead, Buckner, Nick Bosa, Dee Ford and even Solomon Thomas, to a lesser degree, dominated the conversation. Yet, Day became a consistent presence within the rotation and even started games down the stretch.

The 2016 fourth-round defensive tackle might search for a full-time starting gig. If he does, San Francisco will lose an effective interior pass-rusher.

Placing those three defenders aside for a moment, defensive backs coach and pass-game coordinator Joe Woods is expected to leave, as well. ESPN's Adam Schefter reported he is "on track to become" the Cleveland Browns' next defensive coordinator.

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"I just think at this point in my career, after being a coordinator in Denver, I felt as a position coach, I feel like I've been around the league long enough, I felt my reputation was good enough, that if I signed a one-year deal and it didn't work out, I'd be able to find employment," Woods said Wednesday, per NBC Sports Bay Area's Matt Maiocco. "I was basically betting on myself."

The coach certainly did, and it looks like he'll once again lead another defense after helping construct the league's No. 1-ranked pass D. Obviously, Saleh remains in place, but losing a quality coach is never preferable.

Offensively, the 49ers didn't acquire a true No. 1 wide receiver until the middle of the regular season and could just as quickly see him leave. Emmanuel Sanders became an ideal fit in Shanahan's scheme. He was open to make the biggest play of the game (and his career) late in the fourth quarter with the 49ers trailing. Unfortunately, quarterback Jimmy Garoppolo overthrew his intended target.

In 10 regular-season contests, Sanders caught 36 passes for 502 yards and three touchdowns. More importantly, he helped expand the 49ers offense with his precise route-running while simultaneously assisting the younger receivers on San Francisco's roster.

Sanders, who turns 33 before next season, is likely looking for his last significant contract.

Center Ben Garland, tight end Levine Toilolo and defensive end Ronald Blair are free agents, as well. Running back Matt Breida and wide receiver Kendrick Bourne could draw interest in the restricted free-agent market.

Early looks at next year's roster remain positive, but further hits could be forthcoming if soon-to-be 36-year-old offensive tackle Joe Staley decides to retire and the 49ers front office chooses to save $5.25 million by not picking up fullback Kyle Juszczyk's 2020 club option.

San Francisco's roster can't possibly be as loaded next season.

On top of that, the questions regarding Shanahan's approach won't go away anytime soon. For the second time in his career, his wizardry as a play-caller left much to be desired in the biggest moments, as The Athletic's Chris Vannini noted:

Locker rooms expect to lose some players every offseason. No team features the same roster year after year. The constant churn is simply a fact of everyday life in professional football.

So, the idea San Francisco will almost certainly lose key performers this offseason isn't groundbreaking news. However, the combination of those potential losses and the potential hurdle of lost faith in the team's leadership can't be overlooked.

"I believe in Kyle just as much as he believes in us," wide receiver Deebo Samuel said after the Chiefs' 10-point comeback victory, per Around the NFL's Nick Shook. "He got us here, and we'll follow his way."

History doesn't agree with the rookie receiver.

According to ESPN Stats & Info, Shanahan's teams have been outscored 46-0 after establishing 10-point fourth-quarter leads in the Super Bowl. The Atlanta Falcons definitely didn't rebound after their devastating loss to the New England Patriots. The 49ers will be asked to do so with a less-talented roster.

A declining talent pool and the mental hurdles necessary to overcome a devastating loss portend a difficult path to navigate for Shanahan's 49ers if they're ever to make another Super Bowl appearance during his tenure.

Brent Sobleski covers the NFL for Bleacher Report. Follow him on Twitter @brentsobleski.