When Sam Darnold was informed by Jets head coach Adam Gase on Thursday night that the doctors recommended he not play Sunday in Philadelphia, the quarterback was gutted.

Darnold’s first words to Gase were: “I feel like I’m letting the other guys down.’’

“It’s not about him,’’ Gase was quick to say Friday.

Truer words were not spoken this week around Jets camp.

This is about the Jets not named Sam Darnold — specifically those on the offensive line, which has been an abject mess this season despite being one unit on the team that hasn’t been affected by a rash of injuries.

There’s a well-worn cliché in football that says: As a team’s offensive line goes, so goes the offense.

With Darnold about to miss his third consecutive game with his spleen still enlarged as a result of mononucleosis, and third-stringer Luke Falk set to start for a second consecutive game, that axiom applies tenfold for the reeling 0-3 Jets.

If their offensive line, which is likely to be tweaked lineup-wise for Sunday, doesn’t lead the way, the Jets will be as lost and non-competitive offensively as they were in their last game, a 30-14 loss to the Patriots two weeks ago.

“It’s always been on us,’’ left tackle Kelvin Beachum said. “As an offensive lineman, you understand that you don’t get credit when you win and you get all the [blame] when you lose. We accept that. We signed up for this. It’s up to us to go out and execute.’’

There will be a heavy onus on the offensive line to do more in an effort to make up for Falk’s inexperience and limitations. This is a potential danger for the Jets, who simply need their offensive linemen to work in concert and — to borrow that Bill Belichick phrase — just do their jobs.

“We can’t salvage those three [losses] in one game,’’ Beachum said. “We can’t get into trying to press. At the end of the day, we’re all playing for one another. All of our hopes and dreams are intertwined.’’

The way this season has spiraled so quickly — losing Darnold after only one game and the offense having produced only one touchdown in three games — those dreams have been more like a nightmare.

Listening to Gase on Friday, it sounded as if he acknowledged that it’s going to take a near-perfect game from the offensive line to overcome the Eagles, who are two-touchdown favorites.

“For us to play [well] against this [Eagles] group, we have to do a lot of things right,’’ Gase said. “We have to be great up front. That’s where it’s all going to start.’’

Left guard Kelechi Osemele, who was supposed to be one of the key offseason acquisitions to a rebuilt offensive line, quietly has been a disturbing disappointment. He was sidelined the past two days in practice with what Gase described as a shoulder injury sustained Wednesday and isn’t likely to play Sunday.

Reading the tea leaves, it sounded as if Osemele was going to be benched in favor of Alex Lewis anyway. And, a conversation on Friday that can be best described as politely evasive, indicated that was the case.

Asked if he’ll play Sunday, Osemele said, “No idea. They haven’t told me. I don’t really have any say whatsoever. I just work here.’’

Asked if he’s healthy enough to play, he said, “I don’t know. That’s up to the trainers. We’ll see on Sunday.’’

Asked how he feels physically, he said, “I’m feeling good.’’

Asked what’s been missing with the offensive line, he said, “I really couldn’t say, man. It’s up to the coaches. That’s a question you’ve got to ask them. It’s up to the coaches to try to figure out what they want to do.’’

To his credit, Ryan Kalil, the veteran center the Jets signed out of retirement during training camp and who has had his own struggles, acknowledged that however good the effort has been from the line, it hasn’t been good enough.

“No one is more disappointed than our group up front,’’ Kalil said. “We don’t have a talent problem. We don’t have an effort problem. We have a problem in how we’re playing together.’’

Kalil, who’s in jeopardy of being replaced Sunday by backup Jonotthan Harrison, sounded almost prepared for being benched.

“There’s a lot capable guys in the room,’’ Kalil said. “We keep moving pieces, and rightly so until we figure out the best group to get it done. It’s a production-based business.’’

And without positive production from the offensive line, the Jets — just as two weeks ago at New England — will have zero chance to win Sunday in Philadelphia.