For most of the year, Marcus Stroman’s spot in the rotation has been in flux.

It started in spring training.

It continued when he landed on the injured list with left knee inflammation following three starts.

Shaky rehab starts didn’t help. 

Upon his comeback from an extended break on Sunday, Stroman argued for a spot in the Yankees’ future pitching rotation. He delivered five effective innings, giving up only three hits and one home run, using merely 74 pitches in the process.

Even as the injury lingered, with the discomfort stemming from an ACL tear and surgery back in 2015, Stroman never wavered in his thinking about whether he could return to the level of pitching that helped the Yankees defeat the A’s 12-5 to close their series in The Bronx. 

“I tore my ACL and made it back in five months,” Stroman said, “so I don’t do doubt. So I knew I’d be back at some point, it was just a matter of when.” 

He encountered a brief scare early in his outing when Max Muncy’s comebacker drilled him in the hamstring with one out in the second. It “crushed” him, Stroman said. “Pretty firm,” he added, while acknowledging that he’ll almost certainly feel something Monday.

But after a visit from manager Aaron Boone and a trainer — and one warmup pitch to catcher Ben Rice — Stroman never considered exiting. 

“Adrenaline is a great drug,” Stroman said. 

Boone acknowledged pregame that Stroman wasn’t built all the way up, and the 34-year-old had collected a 6.97 ERA across three rehab starts with Double-A Somerset. A smooth return to the majors was far from guaranteed.

But Stroman didn’t surrender an extra-base hit until A’s catcher Willie MacIver homered in the fifth, and Jazz Chisholm Jr. helped him escape a jam in the third by starting a nifty double play.

Stroman also used a pitch mix — with his sinker, cutter and different breaking balls — that was a “little unpredictable,” Boone said. 

Still, the path to consistent starts will continue to remain complicated.

Luis Gil could begin a rehab assignment soon after another live batting practice or two.

Ryan Yarbrough, who can start and pitch out of the bullpen, became an unexpected success story before landing on the injured list earlier this month. 

The first challenge for Stroman involved returning from his knee injury.

He isn’t concerned about any soreness lingering between starts.

The next step will involve the results, given his 11.57 ERA in three outings to open the year.

And Sunday marked an important glimpse of progress for both layers. 

“I just feel like I’ve done a really good job putting my body and my mechanics in a better position,” Stroman said. “… It’s been a process, but yeah, I feel good. I feel like this was a good building block to the next start.”