Hal Steinbrenner calls Brian Cashman. The son channels his impetuous father and tells the Yankees general manager that one championship in two decades is unacceptable, especially when the Red Sox have won four.

Inspired by the gung-ho fervor of the Clippers and Lakers in the last few weeks, Steinbrenner tells Cashman to think title or bust. Don’t worry about expanding budget or expending prospects. Do whatever is necessary to get a parade.

This made-up scenario underscores the Yankees’ real trade deadline problem. Even if Steinbrenner were willing to do what he will not and Cashman were to act in a way he believes counterproductive to running a good organization, there is no Anthony Davis no-brainer for which to literally give up the farm.

The Yankees’ greatest need is a no-questions-asked-he’s-starting-Game 1 arm. That population, in general, has dwindled in this era and, in specific, is non-existent in this market. The chances to get Justin Verlander or Max Scherzer in trade or free agency, respectively, is in the past. Philadelphia (Aaron Nola) and Cincinnati (Luis Castillo) are not parting with young aces.

The one true ace on an also-ran is Jacob deGrom. And the Mets have shown no inclination to trade the righty in this market and, even if they did, they would not deal him to the Yankees. When it comes to potential trades with the Yankees, Mets ownership asks its baseball operations if the swap has a chance to embarrass the team. The answer always has to be yes. Even Jay Bruce or Neil Walker can hit a walk-off homer to decide a playoff series — which is why they ended up elsewhere in 2017 despite a Met dalliance with the Yankees.

DeGrom can haunt for the next half-decade. Which is why the Met baseball operations folks just take the next deal because why even run that risk?

Besides in the Laker/Clipper scenario, the Yankees would have to part with Gleyber Torres to head a package and the equivalent of giving up all the NBA draft picks would be to absorb the rest of Robinson Cano’s contract and no matter how Boss-ian Hal is feeling, he is not approving all of that.

So where does that leave the Yankees?

First, let’s come to peace with their current status. To begin Monday, Baseball Prospectus gave the Yankees a 9.9% chance to win it all, Baseball Reference 11 and Fangraphs 15.6. All had the Astros and Dodgers ahead of them and Reference also had the Twins. This sounds right. If the season were played 100 times, I think the Yanks win the World Series 10-20 times, with it more toward 20 with better health than the first half and the return in full of Dellin Betances and Luis Severino

Which leads to what the Yankees should do before the deadline — if you cannot get an ace, then add both a high-end starter and reliever. Gain greater depth and protection. Pick one from Madison Baumgarner, Trevor Bauer and Marcus Stroman and one from Will Smith, Ken Giles and I would certainly call the Cardinals and see if they were frustrated enough with their plight to want to get out of Andrew Miller’s 2020 money.

The Yanks must prevent 2015 from repeating. They had a seven-game lead on July 28 and stayed mostly unchanged while Toronto restocked and then blew by New York to win the division. Tampa Bay has a run differential similar to the Yankees. The Rays are not going away and they are very likely to add in the coming weeks.

What threatens the Yankees in the AL East is further deterioration of the staff. There is fragility with pitchers such as James Paxton, CC Sabathia and Masahiro Tanaka. Plus, the Yanks have been good enough to have to rely on Zack Britton, Aroldis Chapman, Tommy Kahnle and Adam Ottavino often, which threatens their effectiveness.

For this exercise, let’s give the Yanks Bauer and Smith. If the Yanks add that kind of quality they become better insulated to win the AL East for the first time since 2012. Come the playoffs they might not have an ace, but if they were to add two and somehow get Severino and Betances back in full, the Yanks would have 14 pitchers to choose for 11-13 spots — Bauer, Smith, Severino, Betances, Paxton, Sabathia, Tanaka, Britton, Chapman, Kahnle, Ottavino, Domingo German, J.A. Happ and Chad Green. And the depth shields them should someone go down and/or Betances/ Severino never return

Severino is close to an ace if he gets back in full, but even if he doesn’t Aaron Boone would have myriad arms from which to attack. He can send out a traditional starter — a Bauer, Paxton or Tanaka — and if they are going well, just let them run. But if not, there would be depth to attack playoff games early with reams of quality.

An ace would be better. But deGrom is not walking through that Bronx door. Quality depth is the next best alternative in trying to win a title.