Two weeks in, two starting pitchers gone.

That’s some depressing math for the Mets, whose rotation depth got noticeably shallower in very short order with Monday’s reveal that Sean Manaea will open the season on the injured list with an oblique strain. Projected return for the team’s No. 2 starter? The initial estimate is mid-to-late April.

A week earlier, Frankie Montas was lost to a lat muscle strain that could keep him sidelined until early June. Two-month shutdown, another spring training buildup, and that might be a best-case scenario, given Montas’ lengthy injury history before signing a two-year, $34 million contract in December.

President of baseball operations David Stearns put on a master class in rotation-building last year by turning a bunch of promising high-ceiling retreads into walk-year wonders. Aside from the perpetually banged-up Kodai Senga, who supplied 5 1⁄3 regular-season innings for his $15 million, the others mostly put up career performances, upgrading Stearns’ six-month franchise evaluation period into an OMG romp to the NLCS.

Understandably, Stearns went back to the same formula for Year Two, spending a fraction of the Mets’ $325 million on the rotation. With owner Steve Cohen driving the bus on the $765 million deal for Juan Soto, as well as making first baseman Pete Alonso the highest-paid player at his position this season ($30M), it was up to Stearns to restock the starting staff in more efficient (frugal) fashion.

Stearns already had done it once, with remarkable success. And Senga wasn’t his signing anyway — that was the handiwork of his predecessor, Billy Eppler. But banking on lightning to strike twice can be a very risky gamble, and the odds are catching up to Stearns in a hurry.

To think the Mets actually were planning to use a six-man rotation. At the moment, they’re down to a top three of Senga, Clay Holmes and David Peterson, followed by, in no particular order, Griffin Canning, Paul Blackburn and Tylor Megill. Looking at that group, it was hardly a surprise that one of the first questions asked Monday in the wake of the Manaea injury involved the physical well-being of Senga.

“As of right now, everything is good,” manager Carlos Mendoza said. “I don’t have anything to report there.”

Until Senga shows us he can take the mound with any regularity, which hasn’t happened since 2023 — and after baffling the Mets all last season — the ghost-fork specialist gets an asterisk.

We’d actually have more faith in converted closer Holmes, and he hasn’t made a start since his 2018 rookie season with the Pirates (1-2, 7.80 ERA, 15 total innings).

As for Peterson, is it reasonable to believe he can follow last season’s breakout performance (2.90 ERA, 21 starts) with a similar encore?

Stearns could get lucky again. The hidden genius of piecing together a rotation of B-listers? They’re not as difficult to replace when one goes down. Shrugging off Montas’ absence didn’t figure to be a problem, other than swallowing hard on his salary. It gives someone else a chance to step up in spring training, and that’s a silver lining of sorts as long as Montas doesn’t develop other complications during his rehab process.

Manaea, however, is in a different category. He figured to be among Stearns’ safer bets, as reflected by the Mets’ three-year, $75 million investment, but there are no guarantees.

Manaea’s reinvention after studying Chris Sale’s slingshot delivery led to a stellar second half, and his affection for the Mets definitely made it easier for a winter reunion. But he clearly was running on fumes by the end of the Mets’ playoff drive, which brought his innings total to a little over 200, including a career-high 181 2⁄3 during the regular season.

That’s a hefty workload these days, especially for a pitcher who turned 33 earlier this month, and Manaea admitted that he felt something in the oblique area upon his arrival in Port St. Lucie. Initially, he tried to work through it, but the problem never went away and an MRI revealed the strain.

“It’s very, very disappointing,” Manaea said. “I hate being injured, not out there pitching, doing my job. It sucks and I’m going to do everything I can to get there as healthy and as quickly as possible. I thought I was doing everything I could this offseason to train and it just kind of popped up.”

The Mets could always go outside the organization for a quick fix. Jose Quintana, who had a 3.75 ERA in 31 starts for them last season, is very much available. Trade talks could heat up again regarding the Padres’ Dylan Cease.

In the wake of Manaea’s injury reveal, the Mets played it relatively cool, remaining confident that both of their injured pitchers will be rotation factors again before too long.

“We are getting tested,” Mendoza said. “We still feel really good with what we have internally.”

As the Mets are discovering, that confidence can turn quickly. Two pitchers significantly hurt in two weeks is about as much as they can possibly handle in late February.

A year ago, the Mets supposedly were cooked after losing Senga, but they instead performed brilliantly without him.

This time, however, the expectations are way higher — and the Mets’ margin for error already is shrinking fast.