Yankees have a surprising new ace they can count on

You ever hear Joe Girardi — or scores of other managers — insist that whoever pitches that day ranks as the team’s ace?

These Yankees have discovered a new twist on that old line, haven’t they? Whoever pitches for them in a given game truly performs like an ace. As long as that contest is not slotted for their actual ace of the prior three seasons, Masahiro Tanaka.

Jordan Montgomery easily prevails in the “most surprising non-ace ace” contest here. And even the rookie’s continued excellence no longer really surprises.

The left-hander put up arguably the finest start of his young big league career Friday night, taming the dangerous Orioles to lead the Yankees to an 8-2 win at Yankee Stadium, their third straight victory in this important homestand against divisional challengers.

“I’m starting to trust myself a little more,” said Montgomery, who agreed this was his best major league appearance “so far.”

“I’m just kind of throwing it in there,” he said, “and whatever happens, happens.”

What’s happening is the Yankees keep plowing forward in what began as a reshaping campaign. At 35-23, they now lead the Red Sox (33-27) by three games and the Orioles (31-28) by 4 ½ in the AL East.

Aaron Hicks went deep twice, including the tiebreaking solo blast in the sixth, and Starlin Castro’s second-inning homer got the Yankees on the board after the O’s took a 2-0 lead in the top of the frame. Gary Sanchez chipped in with a double and single as the Yankees outlasted Baltimore’s young ace Dylan Bundy and then beat up on the bullpen with three runs in the seventh and two in the eighth.

Montgomery, barely on the team’s radar as spring training opened, shut it down after surrendering Jonathan Schoop’s monster two-run homer in the second. He retired 17 of the final 18 batters he faced as he established career bests in innings (seven) and strikeouts (eight), giving up only five hits and walking just one. He leads all major league rookies with 61 strikeouts, and the most impressive might have come in the fifth inning Friday. With two outs, former Met Ruben Tejada on third base and the game still tied at 2-2, Montgomery fanned All-Star Adam Jones on five pitches.

“I know he had hit a fastball in the first inning,” Montgomery said, referring to Jones’ single. “I wanted to show that then. I went hard away, went after him with curveballs until he swung at them.”

“We’re giving him smaller bits and pieces. It’s kind of what you do with young players,” Girardi said. “You want to see them clear hurdles. He continues to clear them. We really like what he’s doing.”

Montgomery now owns a respectable 3.55 ERA, placing him third among Yankees starters, behind Luis Severino (2.90) and Michael Pineda (3.39) and just ahead of CC Sabathia (3.66). The Yankees’ widely believed liability has turned into a clear strength. Except for the widely believed anchor of this group, Tanaka, whom the Yankees announced Friday would take an extra day of rest to skip another potential beating from the Orioles and instead try his luck against the Angels at pitcher-friendly Angel Stadium in Anaheim, Calif.

This has been more of a concern than a full-blown crisis because Tanaka sticks out among his group precisely the opposite way of what we expected.

“You can’t ask for any more than what these guys are doing,” Girardi said. “[Severino] is on the mound [Saturday night]. Let it continue. He’s been throwing really well, too. We’ve been in a really important stretch here, so we’ve got a chance tonight to win the first game. We did it. Now let’s go out and try to build on it.”

They have been building on this ambush campaign since the season’s first week, flipping the script and defying conventional wisdom. With so many overachievers here, Montgomery gets easily overlooked in favor of fellow pitchers like Severino and fellow rookies like Aaron Judge.

“It [doesn’t] matter to me,” Montgomery said. “I’m just going to go out there every fifth or sixth day, give them seven or eight. Try to win games.”

An ace like that shall lead them, it seems, four days out of five.