Yankees starting pitcher Masahiro Tanaka pitches against the Boston Red...

Yankees starting pitcher Masahiro Tanaka pitches against the Boston Red Sox during the first inning at Fenway Park in Boston on July 25, 2019. Credit: CJ GUNTHER/EPA-EFE/Shutterstock/CJ GUNTHER/EPA-EFE/Shutterstock

BOSTON — Right around now, a middle-of-the-rotation starter, like a Marcus Stroman or Robbie Ray, doesn’t sound so bad for the Yankees.

Because at this moment, after what we’ve seen the last time through, the Yankees don’t have anything resembling one.

Never mind an ace, or even a solid No. 2. Currently, this is a collection of BP pitchers, and Masahiro Tanaka finished off this nightmarish turn with arguably the worst start in franchise history during Thursday’s embarrassing 19-3 loss to the Red Sox at Fenway Park.

With the Yankees’ bullpen already exhausted, Tanaka was forced to absorb 12 hits and 12 runs in only 3 1/3 innings, raising his ERA from a pedestrian 4.00 to a gruesome 4.79 in his abbreviated night’s work. That alone was unsettling enough for the Yankees, especially from their presumptive No. 1 come October.

But Tanaka was no outlier. Just a continuation of a disturbing trend that has to make Brian Cashman rethink what he’s willing to surrender for rotation help by next Wednesday’s trade deadline. Over the last five starts, dating to Sunday, the Yankees’ rotation has an 18.34 ERA, a stretch of futility that’s not easy to string together.

The only positive? Maybe the timing of the implosion. Cashman still has almost six full days left to work the phones, and if that means bending to a team’s demands, so be it. He’s losing leverage every night one of his starters climbs the mound, and this weekend -- against a desperate Red Sox team at Fenway -- doesn’t feel like the ideal spot to get back on track.

“One hiccup from every one of the guys has come in succession,” Aaron Boone said. “That makes it difficult.”

Hiccup is putting it mildly. This feels more serious, and contagious. For Tanaka to be non-competitive, to this degree, is worrisome. Since the earned run became an official stat in 1913, Tanaka’s dozen is the most ever allowed by a Yankees’ pitcher against the Red Sox. Thursday was set up to be his chance to stop the bleeding, as the ace is supposed to do. Instead, Tanaka became part of the problem rather than the solution.

“There’s a lot of disappointment,” Tanaka said through his translator.

Big picture, from a regular-season standpoint, the Yankees are fine. They still have a 9 1/2-game lead over the Rays and remain 10 ahead of the Red Sox. The AL East shouldn’t be in jeopardy. But this recent skid isn’t helping with the October jitters, and who knows? If this “hiccup” turns into a longer tailspin, and the bullpen suffers because of it, there could be far-reaching ramifications.

Cashman can’t make a trade without a willing partner, however, and teams hanging around the playoff perimeter is impeding his efforts to upgrade the rotation. The Giants have rebounded into a position where they could ride out Madison Bumgarner’s walk season for a last hurrah with lame-duck manager Bruce Bochy. The Indians also need Trevor Bauer to chase down the Twins in the Central, or secure the wild card. 

And the Mets? Zack Wheeler or Noah Syndergaard definitely would provide a boost, but it’s very unlikely a deal gets done between the crosstown rivals. Beyond that, Cashman can no longer be quite as picky. Stroman remains an obvious choice, given his favorable ground-ball ratio in these juiced-ball times, as well as his flair for the bright lights, and Cashman should be able to pull the trigger on him eventually.     

His rotation is providing less and less reason to say no. The Twins’ series was awful enough, as his starters allowed nine homers and a .389 batting average over just 11 innings -- but the Yankees still won two of three against a potential playoff opponent. Tanaka’s collapse was flat-out alarming, coming from the guy they look to stabilize the rotation.

Tanaka still carries the reputation as a money pitcher, and as long as Luis Severino remains out -- he’s still far from getting on a mound -- the Yankees don’t have anyone that inspires his level of confidence as a replacement. German would seem to be the next one in line, based on this season’s resume, but he has an innings-limit leash that makes his October availability unclear. James Paxton is dangerously inconsistent, J.A. Happ is untrustworthy and CC Sabathia’s worrisome knees could become an issue down the stretch.

Maybe the past five days were just a hiccup, as Boone said. But with the trade deadline looming, and so much at stake this season, how much longer can Cashman wait to find out?