Asked Saturday morning about how he planned to complete at least 18 innings of a doubleheader with a pair of starting pitchers who were not fully built up from injuries, manager Aaron Boone raised both arms with upturned palms: a shrug. 

The concerns around the club then only grew as play began. 

The Yankees made mistake after mistake, including an error and passed ball combining to let in a run and cost Carlos Rodón needed length. An ugly ninth inning featured Cody Bellinger slipping to allow another run and the Red Sox teeing off against Ryan Yarbrough. There also was a questionable green light from third base coach Luis Rojas, which resulted in the best offensive chance of the club’s afternoon being neutered. 

So the Yankees did not play a perfect game, but they were most imperfect when they were on the attack. 

The Yankees again were quiet against a Red Sox lefty, this time Jake Bennett, in what became a 6-0 loss in front of a sellout crowd of 47,314 on a sunny afternoon to start a long day of significant baseball in The Bronx. 

Entering the nightcap, the Yankees (76-59) had alternated wins and losses in their previous eight games and temporarily fell to two games ahead of the surging Red Sox (74-61) for the top American League wild-card spot and 4 ½ games behind the Rays in the AL East. 

For probably its biggest series of the season, Boston stacked its lefty pitchers — Patrick Sandoval on Friday, Bennett on Saturday afternoon, likely a lefty opener in the nightcap and Ranger Suarez on Sunday — to exploit a potential Yankees weakness that sure has looked like a real weakness so far. 

“We’ve scored one run in two games, so we have to be better than that,” Boone said after the club opened the series with seven hits — Paul Goldschmidt’s Friday home run the only run-scorer — and 20 strikeouts. Of those seven, all were scattered: They had not logged multiple hits in any frame. 

Without Aaron Judge and Giancarlo Stanton, Boone on Saturday turned to righties such as Goldschmidt (0-for-4), Amed Rosario (0-for-4 with a baserunning mistake), Heliot Ramos (1-for-2 with a double that was wasted) and Ali Sánchez (0-for-2 with two strikeouts and a harmful passed ball). Some of the Yankees’ best bats, such as Luis García Jr., Trent Grisham and even the reasonably hot Jazz Chisholm Jr. and Austin Wells, came off the bench.

It did not help that the Yankees ran themselves out of their best opportunity against Bennett. 

In the fourth, the Yankees got a rare base runner when Rosario reached on a one-out error and took second on a passed ball. 

Ramos then stepped into a Bennett fastball, doubling to center over a turned-around Ceddanne Rafaela. Rosario had been hovering around second in case the ball was caught and then did not stop as Rojas’ windmill kept blowing him home. The Red Sox’s relay — Rafaela to Nick Sogard to Adley Rutschman — was perfect, nailing Rosario by a few steps. 

Boone was OK with Rojas’ send and less OK with Rosario’s baserunning. 

“We got to be in a better position to score,” Boone said of Rosario, who then watched Bellinger strike out to strand Ramos. 

The Yankees did not reach second base again during their eighth shutout of the year. They only logged five at-bats with runners in scoring position — including three in the fourth, when Spencer Jones, Sánchez and Goldschmidt went down to strand José Caballero — and Ramos’ knock was the only hit in such situations. 

“You got to give [Bennett] credit,” Rosario said through interpreter Marlon Abreu. “I think today he was able to mix his pitches very well, use the four-seam, the sinker, the changeup.” 

Four runs on four hits and two walks against an exhausted Yarbrough in the ninth — aided by Bellinger’s slip on the warning track enabling Andruw Monasterio to score — turned a two-run game into a rout. 

One run in the fifth — when Rutschman reached second on a Rosario error, reached third on an infield single from Sogard on a play third baseman Caballero could not complete, and scored on a passed ball in which he beat Rodón to home plate — stuck out as particularly emblematic of the afternoon. 

“On the heels of a night where we didn’t score and played really well,” Boone said, “we played poorly today. Simple as that.”