The narrative has been well-discussed all year — the Yankees awaiting a shot in the arm in the form of a pitcher returning from injury late in the season.

That was once Jordan Montgomery’s claim before Luis Severino and Dellin Betances made it even more popular.

Severino and Betances are the big arms nearing a potential return to pinstripes, but Montgomery may not be far off from being an option to help the Yankees, too. The lefty is set to make his second rehab start Friday with Triple-A Scranton/Wilkes-Barre, continuing to build back up after undergoing Tommy John surgery last June.

Before his elbow failed him, Montgomery was a bright spot for the Yankees. Across 35 starts in 2017 and 2018, the 26-year-old posted a 3.84 ERA and struck out 167 in 182 2/3 innings.

“It’s possible,” manager Aaron Boone said this week when asked if Montgomery could make it back to the big leagues this year. “We want to make sure with that injury we do good by him in a long-term sense. … He is doing pretty well.’’

In his first rehab start, Montgomery tossed two perfect innings and struck out a pair on 19 pitches for Single-A Tampa. It was his first game since May 1, 2018.

Like Severino and Betances, Montgomery wasn’t without a hiccup in his recovery process. He ended a bullpen session early in June because of shoulder discomfort, but an MRI exam showed only inflammation. He was shut down for two weeks before beginning to throw again.

Even if he doesn’t have time to build back up as a starter, it’s possible Montgomery could help the Yankees out of the bullpen in September with expanded rosters as they look to secure the AL East and home-field advantage in the playoffs.

“The biggest thing with Monty, obviously with Tommy John is making sure he’s fully back and healthy and in a good place heading into next year,” Boone said recently. “That said, he has been ramping up and really doing well.”