C.J. Mosley’s first season with the Jets officially came to an end Tuesday.

In reality, it feels like it never even started.

Mosley needs surgery to repair a core muscle injury he suffered in the third quarter of the team’s Week 1 loss to the Bills, his first game with the team, leading the Jets to place him on season-ending injured reserve.

“It gives us a chance to get him back in the spring and get him going for the offseason program,” Jets coach Adam Gase said on “The Michael Kay Show” on ESPN Radio.

The Jets signed Mosley to a five-year, $85 million deal in March that included $51 million guaranteed. The Jets hoped he would be the quarterback of their defense.

Against the Bills, he was all over the field for three quarters with an interception return for a touchdown, a fumble recovery and multiple tackles. Then, he hurt himself in the third quarter while breaking up a pass in the end zone.

It initially was called a groin injury, but Mosley said it moved into his core. He attempted to play in October against the Patriots, but looked like he was playing in slow motion.

“It started in the groin and it worked its way up to my lower abs, which sucked,” Mosley told The Post in November. “I tried my best to finish the [Patriots] game, but I was literally playing on one leg.”

Mosley had platelet-rich plasma (PRP) therapy in hopes of avoiding surgery, but he knew that he could possibly need surgery anyway if rehabilitation did not work.

That ended up being the case.

The Jets claimed safety Bennett Jackson off waivers from the Ravens to take Mosley’s roster spot. Jackson spent a few weeks with the Jets early in the season both on the active roster and the practice squad.

For more on the Jets, listen to the latest episode of the “Gang’s All Here” podcast: