In a season of wild twists and turns for the Yankees, Jordan Montgomery has quietly been one of the few constants.

The left-handed doesn’t come in much flash, but he did provide plenty of substance, and he will look to do more of the same Sunday night as he begins a crucial series finale against the Red Sox at Fenway Park.

Director Aaron Boone said Saturday before Yankees win 5-3. “He is more physically mature, and he is more mature mentally and emotionally. He has benefited from the experience he has gained.”

Montgomery has allowed three or fewer runs in 23 of 28 starters this season, holding a 3.55 ERA at the end of Sunday’s series. Aside from a two-week absence in August after testing positive for COVID-19, the 28-year-old started every turn during the turn while becoming a steady presence on the hill.

For the course that had a lot of questions behind Gerrit Cole’s entry into the season, Montgomery provided a solid answer.

“I started to feel really comfortable just being there,” Montgomery said after his final start, after their 7-1 win over Rangers on September 21. I’m just trying to stay where I am.”

Having had a rare clunker against the Mets on September 10, when he gave up seven runs (five win) over 3 rounds/₃, Montgomery responded by giving up only two rounds over 11 ¹/innings with 18 strikes against the Orioles and Rangers.

Sunday will present a bigger challenge against a better attack than his previous rivals, but Montgomery has been consistent against the Red Sox this season – posting a 3.63 ERA (nine runs in 22 ¹/₃ innings) across four starts.

Third on the Yankees with 3.7 wins over substitutions (per baseball reference) – just behind Gerrit Cole (5.8) and Aaron Judge (5.2) – Montgomery has a chance of making a career high in the innings on Sunday. He threw 155²/innings as a rookie in 2017, but after serving 75 combined rounds over the next three seasons, he has accumulated 149 innings/so far this season in another sign of his reliability.

“I think he understands himself and his musical repertoire,” Boone said. “I think he does a really good job of figuring out what works really well for him on a given day because he’s got guns. He’s got a fast ball, a cutter, a sinker and then a really good curveball. [and] change. He does a really good job navigating those first couple runs and figuring out what he was working on that day. It’s been a really good year for us.”