When you’re a team like the Mets — a group that so often these days has been defined by ailing backs and impotent bats — all you’re looking for is someone to shoulder the load for a day.

On Wednesday, after a double dose of bad news, Terry Collins’ beleaguered squad got a few shoulders to do the job, but the mightiest was by far Noah Syndergaard’s.

Hours after learning that Neil Walker’s back pain was lingering longer than expected, and shortly after scratching Juan Lagares from the lineup because of a partially torn thumb ligament, the Mets were able to rest their weight on Syndergaard’s hulking frame, to the tune of an 11-2 shellacking of the Pirates at Citi Field.

Syndergaard pitched 8 1⁄3 innings, allowing five hits and striking out 11 while throwing 115 pitches. Three of the hits were by John Jaso, and two came in the ninth inning, when Syndergaard was going for his first career complete game. He also lost the shutout in the ninth on David Freese’s double. Jeurys Familia got the final two outs, with a second run scoring on Wilmer Flores’ throwing error.

The Mets snapped a three-game losing streak in which they totaled seven runs. It also was only their second win over the Pirates in 12 games. Finally, it proved to be a respite from a battering ram of bad medical reports, from Lagares and Walker, to the possibility of season-ending neck surgery for David Wright. Oh, and don’t forget the stress fracture in Lucas Duda’s back.

But enough with the litany of the injured, because for a few hours Wednesday night, it didn’t matter.

The Mets notched a season-high 19 hits with the traditionally gentle bats of Flores, Kelly Johnson and Matt Reynolds hitting cleanup, fifth and sixth. Johnson (3-for-5, two RBIs) and Flores (2-for-5, four RBIs) homered. Reynolds was 3-for-4 with two doubles and two RBIs.

It was more than enough for Syndergaard, who took the mound to the music of “Carmina Burana,” a Latin cantata best suited to cinematic interpretations of Vikings going into bloody battle, and only got more intimidating from there.

He allowed a leadoff single to Jaso and nothing else for five innings, before giving up back-to-back singles to Jaso and Gregory Polanco in the sixth. No matter, though, since he was able to strike out Andrew McCutchen on three straight pitches — the final one, a 100-mph fastball — to end the inning.

And while their starting pitching did what it does, the Mets were able to improve on one of their biggest weaknesses.

Coming into the game having scored a league-low 135 runs with runners in scoring position, they managed to score three in the first.

Curtis Granderson and Asdrubal Cabrera led off with singles and Yoenis Cespedes walked to load the bases for Flores, who hit a squibber in front of the plate that hit the lip of the grass and died between the mound and first. Pitcher Jeff Locke had no choice but to get the out at first as Granderson scored. With two outs and runners at second and third, Reynolds doubled down the third-base line, good for a 3-0 lead. The Mets scored one more run in the third and three each in the fifth and sixth innings.