Domingo German #55 of the Yankees pitches during the first inning...

Domingo German #55 of the Yankees pitches during the first inning against the Boston Red Sox during the first game of a doubleheader at Yankee Stadium on Saturday, Aug. 3, 2019. Credit: Jim McIsaac

Of all Domingo German’s impressive stats this season, and the list keeps growing, there is one that gives the Yankees cause for concern.

The number is 104, which represents German’s innings pitched. And that number is beginning to feel a tad uncomfortable, even coming off his seven-inning gem Saturday, with a little under two months left in the regular season.

Because now, the target for German is October, and the Yankees’ rather inflexible protocol regarding innings limits for their young pitchers is coming into play. But here’s another thing that can’t be open for debate. German needs to be at the front of the Yankees’ playoff rotation, so they have to devise a plan - we’re assuming it’s already been done privately - to guarantee he’s strong enough to make that a reality.

Whatever schedule they put together also must ensure that German is at his best come October, which can be challenging when a team has to manipulate a pitcher’s schedule. When asked Saturday if adjusting his routine, or workload, would potentially affect him down the stretch, German didn’t hesitate with the answer.

“Probably, yes,” German said through an interpreter.   

German (14-2) again showed how critical he is to the Yankees’ title hopes by shutting down the Red Sox for seven innings in Saturday’s 9-2 victory in Game 1 of the split-doubleheader. Not that anyone required further convincing. He struck out seven without a walk, and the only two runs came on a pair of solo homers. This was all performed in front of another sellout crowd (46,625) at the Stadium, more evidence of his unflappable ease on the big stage.

“I would say maybe that’s one of the biggest things that stood out to me about Domingo all year,” Boone said between games. “I felt like he came into spring with that attitude.”

Back in February, German was a luxury. The Yankees’ rebuilt rotation was full. But over time, Brian Cashman’s best-laid-plans have blown up on him, first losing Luis Severino and then his other veteran starters coming up too small, too often. Amid the unsettling chaos, German - who turns 27 Sunday - has established himself as the one of the most reliable arms, if not the staff’s legitimate No. 1.

Cashman’s failure to produce another elite starter by Wednesday’s trade deadline only served to accentuate German’s importance. His 14 wins are tied with Justin Verlander (14-4) and Lance Lynn (14-6) for tops in the AL, and it’s the second-highest total by a Yankee in the last seven seasons, behind only Severino (19-8) last year. German also is 8-0 with a 3.18 ERA in nine starts this season against the AL East, which the Yankees are pretty much wrapping up this weekend.

And while we’re talking playoffs, German is 7-1 with a 2.19 ERA in nine games (eight starts) at Yankee Stadium this year. As the rest of the rotation has been hit hard lately, German became the first Yankees’ starter to record an out in the seventh inning since the All-Star break, against the powerful Red Sox, no less. When he whiffed Andrew Benintendi to end the sixth inning, the normally reserved German bounced off the mound, pumping his fists and yelling in triumph.

“Just a little bit of raw emotion there,” German said through a translator. “A lot of people talk about trades and all that stuff, but it was just exhaling, you know, that kind of energy because we’ve been battling all year.”

So has German, who clearly is back to full potency after missing close to a month with a hip flexor strain. The trick is keeping him that way after he threw only 94 innings last season, due to an ulnar nerve injury, and that was following a career-high 123 2/3 innings in 2017. Typically, teams want to stay within a 30 percent jump from one season to the next, but German’s uneven workload makes him more difficult to pin down.

That could put him anywhere from 130 innings to 150, and he’s on pace for roughly eight more starts right now, a track that would put him over. The Yankees won’t divulge their number, but Aaron Boone suggested something will need to be tailored for him over the next two months.

“Yeah, I mean, maybe,” Boone said. “Now he’s up over 100 innings, but I still feel like he’s strong and feel like there’s a lot left in there. But we’ll also try to be mindful of it and smart about it as well.”

When I raised the possibility of German’s innings limits putting him in jeopardy for the postseason, however, Boone quickly - and emphatically - shot that down.

“No, no, no, no,” he said. “Not at all. You got to get there first. But I expect him to be a big part of it.”

Right. German has made himself an essential piece in the Yankees’ pursuit of No. 28. Now they just have to figure out how to make the other numbers add up in his favor.