It’s been six months since Robert Quinn was traded to the Dolphins, but it feels like he’s been waiting much longer than that for Sunday’s season opener against Tennessee.

Quinn’s a former all-pro whose career got off track during three frustrating seasons with the Rams that were marked by injuries and playing out of position. He believes this year, with a new organization and the opportunity to move back to defensive end, will be his return to greatness.

"I’m excited for myself personally and to see the way this team has grown over the past few months," he told The Post after practice today. "I’m excited about playing football again. When I got traded out here, I needed a breath of fresh air and I finally feel like I’m breathing again. Just being around a good place and great people who make it fun to work has been good. Hopefully Sunday I’ll show up."

Miami is certainly hoping for that, too, considering Quinn is the centerpiece of their defensive renovation. Not only is he happy to put his days as an outside linebacker behind him, he’s also in his preferred spot of rushing from the quarterback’s left, which is perfect since Cameron Wake likes to go at the right tackle.

After a year in which the team spent big on its defensive line but finished 26th in sacks and 28th in opponent passer rating, it reallocated its spending from defensive tackle to defensive end.

After incurring an NFL-record dead salary cap hit to release Ndamukong Suh, three of the Dolphins’ top five cap numbers this year are defensive ends. Quinn is this season’s most expensive player at $11.4 million, followed by Andre Branch at $10 million, and Wake is fifth at $9.6 million.

Their thinking is that the combination of Wake and a rejuvenated Quinn will put enough pressure on the opposing quarterback to make it worth it, and the rest of the plan involves significant snaps for Charles Harris, Branch and William Hayes to keep everybody fresh all year.

"I get to stay on the side I prefer to play on — that’s one plus," Quinn said. "I’ve got my hand in the dirt again. And we’ve got Cam Wake, Will Hayes, Charles, Branch — We’ve got a great group of d-ends we can just rotate through."

The upside of Quinn is the possibility that he gets back to peak form, where he was at when racked up 40 sacks from 2012 through ’14. He had 17.5 in the three seasons since, missing 14 games along the way.

He was in a 4-3 defense during those great years, like he is now, and that simplifies his role. He’s in a defense "he was raised in," as coach Adam Gase put it, and he no longer has to worry about dropping into coverage or anything else that’s required of linebackers.

The other factors help, too. He’s totally healthy, he’s working with coaches and teammates that he likes and he got a much-needed change of scenery. He’s only 28, by the way, which means he’s not too old to get back to his prime. Everything is set up for him to make a comeback, and it’s hard to imagine anyone in the Miami locker room is as eager as he is for this season to begin.

"It is a new chapter," Quinn said. "It’s a new city, new area code, new everything. It’s a new start. But it’s still football, so I’m not trying to make it bigger than it is. New city, but same game."

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