MOOSIC, Pa. — With expanded September rosters, an impressive left-handed arm who can pitch multiple innings could be a sensible Yankees call-up.

It would be the sensible culmination of the insensible rise of Stephen Tarpley, a bullpen piece who has emerged after a series of essentially accidents.

At 25, Tarpley is not a kid. He started his career in 2013, a third-round draft pick out of USC who went to Baltimore as a starter. His value rose enough that the Orioles dealt him, their 13th-best prospect, to Pittsburgh in a package for outfielder Travis Snider before the 2015 season. In 2016, Tarpley largely struggled in 20 starts with High-A Bradenton before the Yankees chose him as the player to be named later in the trade that sent Ivan Nova to Pittsburgh.

Tarpley showed up to spring training with the Yankees last year with a shoulder ailment that kept him out until mid-June. When he returned, his job had changed.

“It was like, ‘We’re going to move you to the bullpen, try to give you some innings,’ ” Tarpley said this weekend at PNC Field, where he has become a reliable reliever for Triple-A Scranton/Wilkes-Barre. “I was a starter at the time, and there weren’t many spots available. And I was like, as long as I get to play I’ll be fine.”

Turns out, he was better than fine. In an abbreviated 18-game season, he pitched to a 0.88 ERA, striking out 42 in 41 innings and finishing the year with Double-A Trenton. This year, for the first time, he’s had a fully healthy season and has continued the domination, putting up a 1.71 ERA in 33 games.

Two trades, countless injuries and one transition out of necessity later, Tarpley is seeing the majors come into view, though he’s not a shoo-in call-up because he’s not on the 40-man roster.

“This is my sixth year in pro ball. It’s been kind of a roller coaster of emotions, going through my whole career,” said Tarpley, who’s from Los Angeles. “As far as just being good in spring training [last year], then getting hurt last second, having to sit out half the year, then coming back and having to figure it all out all over again. It’s been a lot of adversity that I’m going to benefit going through. And that’s all playing out right now, as far as this season goes.”

With a mid-90s fastball, Tarpley has the heat that seemingly each Yankees pitching prospect possesses. Where he separates himself is a hard sinker that keeps batted balls on the ground and in the ballpark — a valuable commodity for a southpaw who could face a lot of left-handed hitters in Yankee Stadium with its short porch.

Entering Sunday, Arizona’s Brad Ziegler led the majors this year with a 72.4 ground-ball percentage, one of two players above 70 percent. Tarpley’s sits at 70 percent across Double- and Triple-A, and he’s allowed just three home runs in 63 ¹/₃ innings.

And he’s not a specialist. Lefties are batting .154 against him, righties just .161, while being used as a short- and long-man out of the bullpen. Ramiro Mendoza comes to mind.

“Brings a lot to the table,” SWB manager Bobby Mitchell said. “He can get out righties and lefties, doesn’t matter who it is. Ball moves all over the place. Throws strikes. … Really good slider against lefties. About as competitive as they come. He brings a lot. He’s got a bright future.”

Mitchell also cautioned he’s not sure Tarpley, who was promoted to Triple-A in late June, is ready for the majors yet. The Yankees also could turn to lefty starter Justus Sheffield and let him debut out of the bullpen. For Tarpley, control has been the issue, and his 3.3 walks per nine innings could use work.

But that hasn’t scared the Yankees, who traded relievers Cody Carroll, Giovanny Gallegos, Chasen Shreve, Caleb Frare and Adam Warren at the trade deadline. Tarpley, who would have to be put on the 40-man roster to protect him from the Rule 5 draft, said he was anxiously waiting for his phone to ring as the July 31 cutoff approached. He appreciates his survival, whatever it means.

“I’m just happy with where I’m at right now,” Tarpley said. “I’m glad the Yankees kept me. Or maybe didn’t talk about me in a trade or didn’t want to give me away, whatever it is. I have no clue. But I’m happy where my feet are. I’m going to keep contributing here for Triple-A and hopefully for the Yankees sometime soon.”

From a third-round starter to a trade throw-in to a converted reliever, Tarpley can feel the roller coaster is nearing an end.

“I’m going to be very excited,” Tarpley said about a theoretical call-up. “I can’t even tell you — it’s probably going to feel like getting drafted, that same emotion.

“… I’ve been preparing for this, so when it does happen, I won’t be way over my head. I’ll be ready to perform the same I did here.”