If arm isn’t issue then what is it?

HOUSTON — With every bad start by Masahiro Tanaka, it’s only a matter of time before the questions begin. Is his elbow healthy? Should he have had Tommy John surgery? Will he make it through the entire season?

Tanaka posted his second straight dreadful outing on Saturday, flushing a 6-0 lead while allowing three home runs for the second time in six days. Jose Altuve’s game-tying shot actually made Tanaka’s jaw drop, which of course surfaced on the web as a GIF within about 15 minutes.

But what if these past two outings had nothing to do with Tanaka’s elbow at all?

The Yankees insist he’s healthy. Tanaka says he feels fine. Who are we not to believe them?

Here’s the thing: If Tanaka truly is healthy, then there may be an even greater challenge ahead of him now than the partially torn ligament in his elbow.

He needs to figure out why he’s become so darn hittable.

Tanaka has proven to be a bona fide ace since joining the Yankees. His first 14 starts last year were as good as we’ve seen in years, and although he had a few bumpy starts in June and July, he never had a chance to work through his problems thanks to the elbow injury that sidelined him for more than two months.

When he came off the disabled list less than three weeks ago, Tanaka looked like his old self, allowing four runs over three starts, striking out 21 batters without issuing a walk in 21 innings.

His last two starts have been another story. Ten innings, 13 runs (11 earned), 17 hits and four walks. Yes, he’s fanned 11, but he hasn’t been able to get out of trouble when he has needed to.

These have been the worst two consecutive outings of his brief big-league career. If it’s not his elbow — and I’ll take the Yanks at their word that it’s not — then what’s the problem?

“It’s really a feeling thing,” Tanaka said through a translator. “It’s just that the mechanics are off and that’s causing my pitches to not go where I want them to. That’s all I can say.”

He better get it figured out soon or the Yankees will be in real trouble.

Michael Pineda has been up and down of late, and the Yankees are clearly concerned about how many innings he will throw this season. CC Sabathia has been a shell of his former self, while Nathan Eovaldi has been a typically inconsistent young pitcher.

Adam Warren has been the team’s most consistent pitcher for more than a month, but he’s likely headed to the bullpen now that Ivan Nova is back from Tommy John surgery.

If you’re waiting for Cole Hamels or Johnny Cueto to save the day before the trade deadline, you’re probably going to be disappointed as the Yankees are unlikely to part with the necessary prospects — read: Aaron Judge and/ or Luis Severino — to land one of those aces in a deal.

They already have an ace. He’s just not pitching like one.

Tanaka spent much of Saturday’s game trying to hit the corners, only his formerly reliable command abandoned him.

“I think this is an outlier for him,” pitching coach Larry Rothschild said. “You’ve seen him pitch too many games where he does have that kind of command.”

That’s what we’ve become accustomed to seeing from Tanaka, which is what makes these past two starts so alarming. If his confidence takes a hit, will he be strong enough to fight through his issues and regain his dominance?

“I’ve had longer stretches where I wasn’t performing well when I was pitching in Japan,” Tanaka said. “I’ll overcome this.”

The other times we’ve seen him struggle, it’s turned out to be a physical issue. He says his current problems are all related to mechanics, leaving the onus on Tanaka and Rothschild to get it fixed.

“He’s a guy that, since I’ve watched him pitch, he’s had really, really good command,” Rothschild said. “Unless there’s something going on there that I have no idea about, I think we’ll get it straightened out.”

With that answer, even Rothschild left open the possibility that there’s something going on that Tanaka isn’t admitting to. Neither Girardi nor Rothschild says he’s worried about Tanaka, but a third straight stinker on Friday will surely cause them to rethink that.

“I’d worry even if he pitched a no-hitter,” Rothschild said. “There’s always stuff to work on and things to do. As long as he’s healthy, I’m not as concerned. Obviously we need him to pitch well here because he’s such a big part of the rotation.”

The biggest part.