SEATTLE -- Getaway day was going swimmingly for the Red Sox, who had built a three-run lead entering the bottom of the sixth and were 12 outs away from making that long flight home from Seattle a happy one.

But on a day manager Alex Cora was down two of his best setup righties (Chris Martin and Josh Winckowski), things got bumpy as the Mariners swarmed back with two in the sixth and four more in the seventh for a 6-3 win over the Red Sox on Wednesday afternoon at T-Mobile Park.

It was a fitting end to a frustrating road trip in which the Red Sox were in every game, but went 2-4, including a pair of walk-off losses in San Francisco.

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With the offense able to cobble together only 19 runs in the six games, it left a heavy burden on a bullpen that has been working overtime for a month due to Chris Sale, Tanner Houck and Garrett Whitlock all being on the injured list at the same time.

In July, Boston’s bullpen worked 118 innings, second in the Majors to San Francisco. Fortunately, reinforcements named Sale, Houck and Whitlock should all be back within the next couple of weeks.

In the meantime, Cora has a tough needle to thread. And it showed on Wednesday.

Kutter Crawford gave the Sox a strong start, firing five scoreless innings for the second straight outing. He was at 81 pitches. Did Cora consider bringing him back out for the sixth?

“No,” Cora said. “Eighty-something pitches. He had to grind. We went to one of our best relievers.”

The normally trusty John Schreiber was first out of the bullpen, and his day unraveled swiftly. Eugenio Suárez belted a one-out double and up stepped Red Sox killer Cal Raleigh. Seattle’s DH worked Schreiber for a 10-pitch at-bat that was capped with a two-run homer that made it a 3-2 game.

“Yeah, I mean, it was one of those days that there were certain guys that were down and we tried to go with John,” said Cora. “That was a good at-bat there, and the guy just killed us the whole season, right? Got a good pitch down in the zone and hit it out of the ballpark.”

Considering that Schreiber threw 27 pitches in the sixth, which already eclipsed his previous high on the season, it was somewhat surprising that Cora went back to him for the seventh.

Schreiber opened the seventh by giving up a walk to Dominic Canzone and a single to Tom Murphy. At that point, Cora went to lefty Richard Bleier.

Why stick with Schreiber after his 27-pitch sixth?

“After that, we knew they were going to pinch-hit for the guys below, so the lefty matchups were coming,” said Cora. “At that point, where we were bullpen-wise, it made sense. It just didn’t work out.”

It didn’t work out because Bleier struggled and the defense didn’t do any favors behind him.

Julio Rodríguez hit the ball to the left side of the infield, and the shattered bat came flying not far from where the ball was going. Third baseman Rafael Devers and shortstop Yu Chang both went for the ball. They collided as the ball slipped through for an RBI hit.

“Yeah, I think that's part of baseball,” said Devers. “We didn’t have the best communication.”

The flying bat didn’t help their ability to communicate.

“Definitely the broken bat was a factor in that play,” said Devers. “It was a little bit of a distraction.”

Later in the inning, with runners at the corners and two outs, Suárez stole second. And as catcher Connor Wong fired the ball, Rodríguez bolted home for the double steal. 

“We had the play,” said Cora. “It was a redirect but the throw took a short hop, and they scored.”

Defensive breakdowns have become an all too familiar issue for the Red Sox.

“We've been talking about defense the whole season,” said Cora. “You see us work before games. We’ve been talking about defense since Spring Training. At the end of the day, we have to make plays. We’ll go over it on Friday and talk about what happened.”