The heavy lifting is done, yet here comes the hard part.

Over the past few years, Brian Cashman has helped overturn an organizational philosophy that favored older, expensive and famous over young, deep and flexible, both in skill and finances.

The 2017 Yankees came faster and went further than expected, reaching Game 7 of the ALCS. Their roster and farm system and future payroll are lined up to produce even better teams. But the step from promise to a parade is perilous.

Think about the 2015 playoffs. The Mets were ahead of schedule, went to the World Series, looked like the future was bright and have regressed since. The Astros were ahead of schedule, won the wild card game (over the Yanks) and then missed the playoffs last year before augmenting so well in the offseason and in-season that they are going to their second World Series ever — a symbol that growth in baseball is not always linear.

Then there were the 2015 Cubs — like these Yankees, a wild card that got to and lost in the LCS. They came back and won it all.

This will be the Yankees’ quest now: To be the Cubs. To use the knowledge gleaned from this deep run and the motivation from not finishing it off to get to the Canyon of Heroes in 2018. Because, unlike 2017, next spring training is going to begin with the Yanks in their historically familiar position as the hunted, as a team with the overbearing expectations.

That is why, I believe, Joe Girardi talked about “mental growth” after his Yankees were eliminated by the Astros. It is easier to get through the season as an underdog. What earmarked the dynastic Yankees that Girardi was part of as a player was that even as fame and fortune and pressure mounted for that group, hunger to win and unity to do so together never wavered. Their mental toughness and physical durability was special. Will it be the same for Aaron Judge and Gary Sanchez and Didi Gregorius and Luis Severino, etc.?

Again, the heavy lifting is done. The Yanks do not need some massive overhaul. If their offseason is re-signing Cashman and Girardi, having Masahiro Tanaka not opt out of his contract, winning the derby for Shohei Otani and having Gleyber Torres be ready for the majors by, say, May next year after Tommy John surgery in June to his non-throwing elbow, then the Yanks are pretty much set. And I think all of that is possible.

But here are some initial thoughts on what needs to occur moving forward:

Fewer strikeouts

The Yankees have a very good offense that could get better if Torres is what his projections say and he joins a core with Judge, Sanchez, Gregorius and Greg Bird.

But one of the reasons it does not travel well (the Yanks were 1-6 on the road during the postseason) is how difficult it is for them to score when there are too many places for opposing pitchers to get whiffs.

The Astros should be the role model. They struck out in 23.4 percent of their plate appearances in 2016. Through internal improvement and bringing in lower-strikeout guys like Brian McCann and Josh Reddick, the number went to an MLB-low 17.3 percent this year while they led in runs by quite a bit and still finished second in homers. In the ALCS, the Yanks whiffed 70 times and the Astros 45, and that was against the Yankees’ high-strikeout pitching. Extending at-bats and getting the ball in play wearied Yankee pitching and forced the defense to make plays.

Astro leadoff man George Springer struck out in 33 percent of his plate appearances in 2014 and has lowered it each year to 17.3 this season. Can players like Judge (30.7 percent), Bird (24.7) and Sanchez (22.9) do even a better job of defining their zone and raise their damage ratio by doing so? Remember the goal now is to not just get in the playoffs, but win there, and one way to do it is be able to handle the best pitching. That trio whiffed in 38 percent of their postseason at-bats.

Stay lean and mean

Hal Steinbrenner and Cashman have vowed the Yankees are getting under the $197 million luxury tax threshold next season. With particularly the contracts of Alex Rodriguez and CC Sabathia coming off the books, it is doable. But it means not a lot of wiggle room for big expenditures, especially if Tanaka does not opt out of the final three years at $67 million.

That is not a huge problem. The Yankees do not have substantial needs. And if Otani comes, then the Yanks are really set up. Because via the new CBA, Otani will cost a pittance of his actual value while deepening the rotation and, perhaps, solving a piece of the DH puzzle.

If the Yanks fulfill the quest to get under the threshold, they will reset their tax burden and be in position to be as aggressive as they want to be in the 2018-19 free agent class that right now would include Bryce Harper, Manny Machado, Josh Donaldson, Dallas Keuchel and, perhaps, Clayton Kershaw.

So every move this offseason will be done within the prism of getting under the $197 million. Such as …

Trade veterans

The Yanks will try to move as much of the $68.5 million over three years Jacoby Ellsbury is owed to save some dough and clarify the outfield. But that won’t be easy. They will listen again on Starlin Castro, Brett Gardner and Chase Headley.

Gardner is so internally valued for his all-around game and leadership that I just don’t think another team would give enough for the Yanks to move him. Headley, entering the last year on his deal, can help at third, first and DH if no club wants him.

I would try to move Castro (two years at $22 million) and I would begin by asking the Mets if they would do him straight up for Jerry Blevins. Castro can hit and despite injuries this year, has been durable and loves to play. But I just think the defense came down a grade and at-bats are going to be undisciplined, and this is the place to get Torres onto the roster next season.

Address Sanchez

You can see that Sanchez is poised to become the polarizing figure on this roster, particularly surrounding his defense. But I actually think he received the ball well for most of the last two rounds. Where he faltered was handling throws to the plate.

Here is the thing: He is still young, a great hitter and there might have never been less catching depth in the sport than there is now. So, with his arm and bat, Sanchez gives the Yanks a catching advantage near daily. But his bat is so special that getting it more and preserving his body should be a key. Thus, have him catch 100 games and DH 50 — with the ideal situation being Otani DH-ing 50 and a rotation of Judge, etc., for the rest, and suddenly there would be no need to pay a DH like Matt Holliday.

To do that, the Yanks might have to upgrade backup catcher. The staff loves to throw to Austin Romine. But is more bat needed if the backup is going to play 60-ish games? If so, Alex Avila, who brings a lefty bat and high on-base percentage, is a free agent. So is Rene Rivera, who is no offensive dynamo, but is better than Romine while still offering strong defense.

Keep the rotation deep

The Yanks will know within three days after the World Series if Tanaka is staying. If so, he joins Severino, Sonny Gray and Jordan Montgomery to form a strong 20-something base. If Otani comes, that is a powerful unit.

Chad Green will be asked to show up to spring as a starter to see if — like Severino — he can translate pen dominance one year to rotation excellence the next. The Yanks believe the strength of their farm system now is pitching depth, and that Albert Abreu, Domingo Acevedo, Chance Adams and Justus Sheffield can become rotation factors as early as next season.

Still, I think Sabathia wants to stay and would do it on a one-year deal that would not be overly burdensome and, if so, bring him back. It allows the stashing of depth that is always needed. Sabathia has transformed himself to a valuable five-, six-inning starter. Plus, he is revered in the clubhouse and with so much youth around, veterans such as Gardner and Sabathia remain valuable.

A luxury item

The Yanks already have a deep, terrific bullpen. But the way the game is played now — particularly in the playoffs — the more interchangeable, high-end pieces the better. So I think they should add a lefty, which is why I suggested Blevins. Since I don’t expect the Mets and Yankees to deal, I would push for Mike Minor, who almost certainly will opt out of his mutual option and be a free agent.

Minor has had a lot of arm issues (he missed 2015-16). But in his first year as a full-time reliever, he appeared in 65 games, handled multiple innings well, was closing by the end of the year, had his fastball tick up to work with his fantastic slider and held lefties to a .423 OPS.

A pen with Minor, Aroldis Chapman, Green, David Robertson, Tommy Kahnle and perhaps a rejuvenated Dellin Betances would mean having multiple high-end weapons available daily and would be a force not just in the regular season, but the postseason even more so.

And after a terrific 2017, this is what the Yankees are about now — that difficult next step.