NFL

Undersized Jets safety Leonhard back with passion intact

He is the littlest Jet with a heart as big as Rex Ryan before lap-band surgery, and now he sat high atop Heinz Field, in the press box, with his crutches, 60 minutes from a Super Bowl for the third straight January, with a broken heart.

His team was in disarray, getting swept away by a black-and-gold hurricane too powerful for 11 men to stop.

“That was the only game that I traveled to after I got hurt,” Jim Leonhard said yesterday, “so that was not the right one.”

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Big Ben Roethlisberger and Rashard Mendenhall were shredding the Jets defense at will, and all Jim Leonhard could do was wish he could do something, say something, anything.

“You’re helpless. You’re standing there, you can’t talk to ’em. You don’t really have a whole lot of input,” Leonhard said. “ It’s extremely frustrating, but that’s part of the deal. You get injured, you’re kinda out of the mix a little bit.”

Now, finally, Jim Leonhard is back in the mix. Eight months that seemed like an eternity following surgery for a fractured right tibia that had no chance of fracturing his Super Bowl obsession.

He wears a white sleeve over his right shin for individual drills, and waits for the trainers to give him clearance for the team periods.

Of course there is apprehension for the first big hit.

“You want to test it that first time and see where it’s at,” Leonhard said. “Obviously you’re a little nervous going in there, you don’t know how it’s gonna respond, but once you do it, you’re kinda like, ‘OK. This is gonna be OK now.’”

He was fearless long before he was a walk-on at Wisconsin, and he has no fear the Jets will be getting anything but the best of Jim Leonhard, all 5-oot-8, 188 pounds of him.

“Definitely confident that I’m gonna be where I was, and hopefully beyond,” Leonhard said. “Anytime you get a chance to sit back and learn and correct some of the issues that you had before, I think it makes you a better football player.”

Even among the behemoths, it is never difficult finding Leonhard. Just find the football and you will usually find Leonhard, Ryan’s Little Big Man.

“He looks for intelligent football players, and I think I would definitely put myself in that category,” Leonhard said. “He doesn’t want a robot. He wants a guy who can think and make adjustments and help out all the other people around him. And loves the game of football. When I think of a Rex Ryan football player, that’s what I think of, and I definitely fit that mold.”

The Bills signed him as a free agent in 2005. The doubters were waiting for Jim Leonhard at every level.

“It’s always, ‘Ah when he gets to the next level, he’s gonna struggle because of his size,’ things like that,” Leonhard said. “But I think I’ve proven everyone wrong.”

How? Here, at the highest level?

“You have heart and have some brains,” Leonhard said, “then you got a shot. You can be lacking in a few areas if you got heart and you got the brains.”

But at the end of one fateful practice eight months ago, Leonhard didn’t have a right leg to stand on, and it left his teammates temporarily traumatized two days before the Foxboro Chainsaw Massacre. “I knew it was bad,” Leonhard said.

Within 45 minutes, X-rays confirmed his season was over, and he underwent surgery that night.

“Everybody loves him,” Eric Smith said.

“You hate to see something happen like that to a good person.”

Smith can’t wait for his safety partner to get the green light.

“Makes my job easier ’cause then I don’t have to run everything,” Smith said.

Little Big Man feels ready.

“It’s one of those lockout casualties,” he said. “The trainers haven’t been able to see me, so I’ve been keeping them updated in the ways that I could. They just want to make sure.”

It is a blessng for Leonhard that there are no more two-a-days.

“And that’s huge,” he said. “You can go out there as hard as you want knowing that you’ve got 24 hours to get your body back.”

And help get your team back — to a Super Bowl.

“The frustration of coming up short three times in a row,” Leonhard said. “ it’s definitely starting to mount up for me, and hopefully it boils over this year, and we get there.”

Don’t sell him — or the Jets — short.

steve.serby@nypost.com