Every positive medical test result, every rehabilitation milestone, every private opinion offered by Saquon Barkley told the Giants he was ready to go.

In fact, the mounting evidence in the left-hand column of a pros and cons list on whether to play Barkley at the start of this season mostly was countered by just one name: Terrell Davis.

Giants general manager Dave Gettleman was a Broncos scout when Davis burst onto the scene with a brilliant four-year start, and he still had connections to the organization when the running back tore both his ACL and MCL in his right knee. Davis hurried back for the 2000 season-opener, but missed 31 of the next 47 games over the final three seasons of a Hall of Fame career cut short by injuries to both knees and the lack of a long-term view.

The cautionary tale was whispered around the Giants facility this offseason, as consideration was given to holding out Barkley for the first two games — played in a five-day span — and until after the one-year anniversary of the game in which he suffered a torn ACL, strained MCL and partially torn meniscus in his right knee. Ultimately, the combination of encouraging factors, including Barkley’s strong drive, put him on the field for Week 1 — and Davis was watching when Barkley caught a pass in space against the Broncos.

“He fell down, and I empathized: That’s unlike him. Saquon would’ve never fallen down,” Davis told The Post. “I remember going to my trainers and saying there was a bit of a lag between what I wanted to do and my body responding to it. It was very slight, but it was on my mind.

“I believe he’s in that phase where he is improving, but he’s not yet where he used to be. That’s going to take some time. As fans, we assume if Saquon is on the field, then he needs to be the Saquon he used to be.”

Barkley, 24, cultivated a superhero’s image by growing tree-trunk quads, hurdling or bulldozing or outrunning defenders, and selling a Nike-branded logo that looks like Superman’s ‘S.’ But great success and labels are his enemy as fans panic that the end results are not the same after a small sample size.

“People probably do expect me to come out here and jump over people and do crazy things,” Barkley said. “Obviously I would love to do that, too. But at the end of the day I am human.”

Barkley is running, cutting and stutter-stepping on his surgically repaired knee, but he is averaging just 3.4 yards per carry, with one touchdown, after three games. Only seven of his 39 carries have gone for more than five yards, but five of those were last week, as he progressed.

So, is this just expected rust on the climb back to top form? Are pedestrian numbers his new normal? Or are other factors, such as play-calling, blocking and running style, behind his slow start? It depends on who you ask.

“He didn’t lose that first-step burst,” said former Pro Bowl linebacker Jonathan Vilma, Fox’s booth analyst on the Giants’ game last week and again this week. “He does not look like he is favoring his knee. But he hasn’t played in a while and he has to get re-used to the speed of the game and the defenses. It’s not anything out of the ordinary. It’s just that they are 0-3, so everyone is trying to figure it out.”

Barkley’s injury happened Sept. 20, 2020, but he delayed knee surgery until Halloween, as a way of healing the MCL. That changed the recovery timetable. Browns receiver Odell Beckham Jr. — Barkley’s close friend and former teammate — had his ACL reconstruction 10 days later and didn’t return until last week.

“It’s a fallacy to say he had an early-season injury. You have to judge him as a Week 8 ACL injury,” said Dr. David Chao, the former Chargers team physician who runs ProFootballDoc.com. “The most realistic thing you can hope for is somewhere in the second half of the season he becomes closer to being Saquon. Realistically, 2022 is when you would hope to have ‘Superman.’ The second year back is always a better year back.”

The Giants’ plan to ease Barkley back or to lighten his workload was scrapped under the urgency of another season about to be lost too soon. He played 85 percent of the offensive snaps the past two weeks, and the Giants are asking him to alter his running style to become more of a north-south power back than a slasher.

“He had a really significant injury last year,” offensive coordinator Jaosn Garrett said, “and how hard he worked to come back and play as much as he has early in the season has been really, really impressive.”

Giants radio analyst Carl Banks, a former Pro Bowl linebacker, said on WFAN that a “blunt conversation” is needed to tell Barkley he is making it too easy for defenses by not initiating collisions.

“It’s time now to expect more: He has proven that he is not a tentative runner in terms of his knee,” Banks said. “Get in the hole, put your cleats in the ground, run through a couple arm tackles, and there are not a lot of players in the NFL defensively that want that smoke when that guy is running downhill. They been coached now to, ‘Hold your spot and he is going to dance around and you’ll just wrap him up.’ ”

Vilma, who had a bone-graft on his knee as a four-year veteran, agreed that it is Barkley’s move in the “constant chess match” after defenders exposed to the back’s rare athleticism learned he wants to beat them to the edge.

“I expect a better Saquon soon,” Vilma said, “and less from the physical side and more from the mental side.”

There are questions around the league regarding whether the Giants understand how to build around Barkley and call plays that utilize his strengths. He is rarely targeted as a receiver. The offensive line — in constant flux and ranked in the bottom half of the NFL year after year — is better in a gap-blocking scheme than a Barkley-suited zone scheme.

“People thought they were getting Ezekiel Elliott, when they got a bigger, stronger Reggie Bush,” one NFL scout said. “They should be treating him like Reggie: Work him in the screen game and stretch plays with RPO concepts so that you are not as predictable.”

Barkley cut twice on a 15-yard run against the Falcons, moving in such a blur that Dr. Chao had to press rewind while watching it.

“His two big cuts were made off of his healthy left leg,” Chao said. “Recovery from an ACL is much more of a slow sunrise than a light switch. To me, he’s exceeding expectations, and everyone who says not, their expectations are too high. So, does he look like himself? No. He will get there. If he weren’t Saquon, he would be on the bench right now, but 85 percent of Saquon is pretty good.”

Davis, who was forced to retire at 29 years old, recently founded the DEFY line of performance and recovery drinks, ranging from high-electrolyte water to those infused with the CBD (no THC).

Though Barkley, 24, is signed only through 2022, the Giants are invested in his long-term health because he is their top game-breaker and top entertainment draw. The Giants and Barkley are hoping a productive season will make an easy decision on his next contract.

“If I’m an executive, I’m not worried about making a decision on him anytime soon. No need to,” former NFL general manager Randy Mueller said. “I don’t know what the rush to judgment is. I’ve seen a guy trying to get his legs. There’s a lot of football stuff that happens that you can’t replicate until you get out there.”

When Barkley drones on weekly about trusting the recovery process, he isn’t just speaking in clichés. He is refusing to make excuses or ask for patience. But he might not even realize it will get better soon.

Advancements and expectations have come a long way since Davis’ career ended because overcompensating for his right knee led to a torn meniscus in his left knee. Adrian Peterson won NFL MVP after tearing his ACL. That’s the new, albeit unrealistic, standard.

“Here’s the challenge and I’ve been down this path: You go from feeling like Superman to a mortal,” Davis said. “On a scale of 1-10, you are a 7, but that 7 feels really good because you were a 2. He’s healthy, but we are used to seeing him on that next level. I have no doubt that will come back. We just have to be patient.”