BOSTON — An already rough series against the rival Red Sox got even worse for the Yankees on Saturday, when DJ LeMahieu sat out a 9-5 loss with a low grade groin strain suffered during an at-bat in Friday night’s loss at Fenway Park.

LeMahieu called it a “real small” strain and said he hoped to stay off the injured list.

“It’s not too bad,’’ said LeMahieu, who had an MRI exam Saturday. “It’s just kind of in a weird spot.”

Manager Aaron Boone said he didn’t expect LeMahieu to start Sunday’s series finale but wouldn’t say he’d be unavailable — though with a day off Monday, LeMahieu could get three straight days of rest.

“We’ll see where he’s at [Sunday],” Boone said. “There’s no decision quite yet.”

The Yankees were also optimistic they dodged a bullet after Gio Urshela rolled his right ankle running the bases on a double in the eighth inning Saturday.

Urshela limped into second, but remained in the game after a visit from the training staff.

He scored easily on a Kyle Higashioka single later in the inning and, following the loss, said he was fine.

“I was worried he pulled something,’’ Boone said. “When he scored he looked pretty good.’’

Boone and Brett Gardner had similar feelings about Gardner’s sore left knee before the outfielder finally went on the IL after missing five straight games.

Since LeMahieu and Urshela have been integral in the Yankees surviving an outrageous number of injuries this season, they can hardly afford to lose both — especially now that they have dropped three in a row to the Red Sox.

LeMahieu has exceeded all expectations, becoming the Yankees’ most consistent hitter this season since signing in the offseason. Urshela has emerged as a clutch hitter and superb third baseman after being thrust into a starting role due in part to Miguel Andujar’s shoulder surgery.

If either LeMahieu or Urshela ends up being shelved, they’ll have plenty of company.

In addition to Gardner and Andujar, the Yankees’ offense is missing Gary Sanchez (groin) and Giancarlo Stanton (knee). The Yankees have also been without Aaron Judge (oblique), Aaron Hicks (back) and Didi Gregorius (elbow) for significant chunks of time this season.

And that doesn’t include the oft-injured Jacoby Ellsbury and Greg Bird.

The Yankees have weathered just about all the other injuries thanks to both LeMahieu and Urshela.

LeMahieu has already set a career-high in RBIs (71) and matched the career-high in homers (15) he set last season with Colorado, while Urshela continues to produce.

What has helped make the Yankees’ lineup so successful is the fact it’s been well-rounded, which has no doubt been aided by the fact the players haven’t been overused and they have maintained depth.

That will be tested again if either LeMahieu or Urshela winds up sidelined for any length of time.