The NFL offseason is about to heat up. And if last season taught the football world anything, it’s that turnarounds can happen quickly leaving teams throughout the league to ask: Why not us?

The Eagles proved that smart roster construction can lead to beating anyone, even the Tom Brady-led Patriots. Philadelphia before winning the Super Bowl went 7-9 in 2016, one off the 49ers’ record for the 2017 season, which included a five-game stretch when they became the first club in league history to lose five straight games by three points or fewer.

They ended the year 6-10 with as much momentum as any non-playoff team in the league. Kyle Shanahan and John Lynch’s first year on the job should be considered a success. They set the cultural foundation heading into Year 2 and locked up Jimmy Garoppolo to a five-year contract.

The financial realities of the league play a big role in teams, like the Eagles, being able to turn things around. The salary cap exploded from $120 million in 2011 to a projected $178 million for 2018, which is another $10-million increase from the previous year. San Francisco will be among the league leaders with $60 million in remaining cap space when free agents can join new teams March 14, not including the room allocated for the incoming draft class.

We’re at the point in the calendar where there will be countless profiles, blog posts and different angles written about how the 49ers can add to the roster to get back to the postseason. Here, we’ll offer a checklist-style manifesto of what to look for as San Francisco tries to get to that next level.

The 49ers last year filled needs in free agency before going BPA in NFL draft

Salary cap space is pliable offering teams flexibility when it comes to constructing their roster. Perhaps that’s why the 49ers last offseason addressed their most pressing needs through free agency to allow themselves the freedom in the NFL draft to address any and all positions.

Cap space can be created in a variety of ways. Take Garoppolo’s contract, for example. The deal is heavily front loaded. He’ll have a $37-million cap figure in 2018 that ensured a massive pay day upon signing, but also gave the team flexibility going forward. Garoppolo’s cap hit for 2019 is just $20 million, leaving the club with $90 million in projected space for that year, according to Overthecap.com.

(Sergio Estrada-USA TODAY Sports)

Money can be converted from base salaries to signing bonuses and players can sign extensions that push payments up or back. There are various tools to create cap flexibility in any given year. And all that cap room makes it even easier to move water from one bucket to another.

The draft, meanwhile, is far less flexible. Teams only get one first-round pick each spring (barring trades) putting those assets at a higher premium, making it more difficult to land high-end players on rookie contracts. Players in free agency are better-known quantities, and teams smart with their spending can add multiple high-level players at a time, like the Jaguars did over the last two seasons helping them go from 3-13 to the AFC title game.

Suffice to say, the 49ers have the wherewithal to add plug-in starters at positions of need, which they did last season when Shanahan and Lynch first took the helm. They had voids at receiver, so they signed Pierre Garçon, Marquise Goodwin and Aldrick Robinson. They needed a fullback, so they landed one of the best in the league in Kyle Juszczyk. Linebacker was a problem area, so they signed Malcolm Smith for his familiarity with the system – although he missed the year due to injury.

“We’re going to be aggressively prudent and always make wise decisions and look out some years and do things, though, that we feel are a fit and give us an opportunity to be a better organization,” Lynch said after signing Garoppolo. “We’re going to make those moves. This (Garoppolo’s deal) takes up some of that room, but that was a trade-off we were happy to make, and we still have a lot left. We’re excited about that, as well.”

Which is why this March could be another busy one for San Francisco’s brass. The top need in the starting lineup is at cornerback, where it can be difficult to thrust a rookie into a primary role and expect immediate results. Fortunately, there are some appealing options in free agency, like Malcolm Butler, Trumaine Johnson, Rashaan Melvin and Kyle Fuller, should they hit the open market.

The options are thinner at pass rusher, leaving Ezekiel Ansah likely as the best available player after logging 12 sacks last season. The guard market is top heavy, but Andrew Norwell, Josh Sitton or Justin Pugh could provide a significant long-term upgrade along the interior of the offensive line.

This spring could be one of the biggest free-agent spending sprees in team history. That’s what the signs are pointing to.