PITTSBURGH — It was ugly. It was grueling. But it’s over.

Now to see if the Mets can stop it here.

The Mets on Sunday completed a stretch of 13 straight games, losing 10. Along the way, they also lost Tylor Megill, Griffin Canning and Max Kranick to injury and witnessed a setback in Sean Manaea’s rehab.

Here are three takeaways from their sweep at the hands of the cellar-dwelling Pirates:

In addition to Megill, Kranick, Manaea and Canning — the latter of whom is out for the season — the Mets lost Kodai Senga to a hamstring strain earlier in the month.

Their healthy starters, meanwhile, aren’t giving them length. David Peterson lasted only 4 2⁄3 innings in the first game against the Pirates and Paul Blackburn, hindered by an 89-minute rain delay between his first and second innings Saturday, went only one inning plus five batters. Frankie Montas pitched four innings during Sunday’s 12-1 drubbing.

All this has led to an overtaxed and porous bullpen that now features a constant rotation of minor-league arms. The Pirates, who boast the second-worst batting average in the National League, scored 30 runs in three games.

Answers are hard to come by, but it looks as if president of baseball operations David Stearns may be forced to make moves sooner rather than later.

The Mets scored only four runs against the Pirates and, aside from Brett Baty and, periodically, Ronny Mauricio, they’re getting very little from the bottom of their lineup.

In the past 15 days, Francisco Lindor is hitting .143, Tyrone Taylor .167 and Luis Torrens .179. The Mets’ biggest struggle is their production with runners in scoring position. They’re hitting .217, and only the White Sox are worse.

“The coaches have done a really good job of preparing us,” Lindor said. “They’ve given us everything we can ask for and . . . it’s on us, it’s on me to execute. [On Sunday], I felt like I got the pitches that I wanted and I just didn’t execute.”

Coincidentally or not, last year’s May 29 players-only meeting marked a distinct turnaround in the Mets’ season, and while Lindor insisted there is no shortcut to this process, the team nonetheless felt it was time to hold another meeting Saturday night after a dreadful 9-2 loss.

Details of the meeting were kept in-house, but several players spoke, including Lindor, Pete Alonso and Juan Soto.

“We’re not playing at our maximum potential right now,” Alonso said. “We’re definitely not playing consistently. We’re playing good games, we’re staying in games, but I think we need to do a better job finishing for sure.”

Some of the focus was on trusting your teammates, passing the baton and playing as a cohesive unit, Brandon Nimmo said.

“I just appreciate the fact that the guys felt the need yesterday to kind of get together in the same room and look at each other’s eyes and express their feelings,” manager Carlos Mendoza said. “From Day 1, I expressed [that] communication [is important].”