The Yankees need Gerrit Cole in 2020. They really need him in 2021. So they have to sign the ace righty or add someone else of substance they imagine being part of rotations beyond just next season.

James Paxton and Masahiro Tanaka are both entering their walk years and J.A. Happ also would be a free agent after the 2020 season if he does not vest his 2021 contract with either 27 starts or 165 innings next year. The Yankees, therefore, might soon be looking at re-enlisting and/or replacing 60 percent of their rotation.

That all three are present next season along with Luis Severino, Jordan Montgomery and, the Yankees hope, Domingo German (who still is awaiting word on a potential suspension in 2020) keeps the team from feeling desperate with its rotation, especially because the Yankees again project to have a strong bullpen and lineup to protect their starters.

Still, this is the area the Yankees want to address most. Brian Cashman is not publicly airing how much of an investment the Yankees are willing to make in a starter. Interested onlookers on other teams have been fairly split in their speculation between:

1. How can the Yankees ignore Cole? He has been their white whale after drafting him and not signing him and then failing to offer Pittsburgh enough before Cole was traded to Houston. They need an ace, and here is one in his prime who costs only money.

2. Money is a huge issue. One executive said, “I don’t believe Hal Steinbrenner any longer authorizes seven years or more at the dollars it is going to take for any pitcher.” The signing of Cole would take the Yankees near or over the third luxury-tax level of $248 million, which Steinbrenner surely wants to avoid.

So which way do the Yankees go? Part of the answer depends on how much they will be influenced by what they have coming and what might be available, especially in free agency.

The Yankees believe they have a lot of intriguing arms climbing through their system with Deivi Garcia and Mike King perhaps positioned to help the 2020 rotation. But the Yankees’ track record is not good here. Only three players who signed their first major league pro contract with the Yankees made 28 starts in the majors last year: Tanaka, Ivan Nova and Caleb Smith, who was the only one of the three drafted by the Yankees. The next-most starts was eight by Manny Banuelos. The next-most by a drafted player, amazingly, was three by Tyler Clippard, who was used as an opener.

Now, German, while not originally signed by the Yankees, received much of his minor league seasoning with the organization. Plus, injuries to Severino and Montgomery impacted these totals, but every team has pitching injuries. The Yankees have restructured a lot of their minor league pitching development programs, so perhaps that will have an impact. But the Yankees are in a championship-contending period and have to have surer things for the rotation.

And when you look to future free-agent markets, there is no one like Cole on the horizon — a prime-aged ace. Paxton and Mike Minor project as the best free-agent starters next offseason. Three starters the Yankees were not all that gung-ho about at the trade deadline last July — Trevor Bauer, Robbie Ray and Marcus Stroman — also are entering their walk years. Remember that Cashman indicated that Ray and Stroman probably would have been used as postseason relievers if obtained.

The following offseason promises one-time aces far into their careers such as Zack Greinke, Clayton Kershaw, Max Scherzer, Justin Verlander, Charlie Morton, Johnny Cueto and — assuming their options were picked up for 2021 — Corey Kluber and Jon Lester. The best starters in their primes would be Noah Syndergaard, Jose Berrios, Eduardo Rodriguez and Lance McCullers Jr., who missed last season after undergoing Tommy John surgery.

There is talent, and there are always surprises who become available in trades — perhaps Cincinnati’s Luis Castillo or Cleveland’s Mike Clevinger go on the trade market. But Cole, in particular, would elevate the Yankees for 2020 and keep them less desperate moving forward. Future rotations would be built around Cole and Severino with the hope the rest of the answers come largely from among Montgomery, German, Garcia and prospects such as Luis Gil, Luis Medina and Clarke Schmidt.

So while they are a win-now team focused on 2020, the Yankees have to consider what they have and won’t have after next season, and how much an investment in Cole would help alleviate approaching problems.