“2 yrs ago I was told I might never walk again. Just WALKED off plane in Indy to play in The #SuperBowl,’’ Herzlich posted on Twitter.

He wasn’t thinking of this moment then, back when he was struggling to beat cancer, struggling to get through radiation. At that point, he was simply trying to survive.

If he thought about football at all, he thought about getting back on the field at Boston College, about finishing the college career that had been interrupted by a terrifying phone call and an even more terrifying diagnosis.

It was Ewing’s sarcoma. It could have meant death. That, to the linebacker, was unacceptable.

“I looked at my dad and said, ‘Dad, we are going to beat this and I’m going to play again,’ ’’ Herzlich said. “He looked at me and he believed me. He was probably the only one that believed me at the time, but we did it together.’’

It was May 2009, his junior year at BC, when the stabbing pain in his left leg finally convinced him that it was beyond normal football soreness. He soon began six months of chemotherapy and five weeks of radiation, and had surgery to insert a titanium rod in the leg.

“It was gut-wrenching, heartbreaking, when you saw him go through it,’’ BC defensive coordinator Bill McGovern said. “But the way he did it with the energy, with the commitment, the determination, and the passion, and the way he was so positive about everything, was just so inspiring.’’

He would undergo six hours of chemotherapy in a day, a draining and crushing exercise. He would know that he needed to work out, to do cardio, to keep his body in as good a shape as possible for the sliver of a chance at football.

Every couple of weeks, he would watch a highlight video that he made himself from his 2008 season, his finger poised on the rewind button. He would see himself succeeding, wiping away the cancer and the hospital beds and the potential for failure.

There was excruciating pain that went along with it, after the surgery, when the scar tissue was kneaded out, the muscle tearing off the bone, the scar tissue tearing away. He would scream on the table, even as he knew this was what he needed to do for the future that he wanted.

And then he returned to Boston College for his final season, and made the Giants as an undrafted free agent. It was the right place for him, a place with a strong BC support network, a place that could use a linebacker with his size and skills.

“He’s a football player, he loves to play and be around it,’’ Giants coach, and former BC coach, Tom Coughlin said. “He wants to be a good football player, and he’s been a tremendous inspiration to us even though he doesn’t want anything to do with that. You have to understand that, and he doesn’t want to be referred to in that way at all. He’s a tremendous example.’’

He wants to be a football player. He survived cancer, sure. But he wants to be recognized for his athletic ability, for what he can do on the field, proving himself each time he’s out there.

Herzlich still goes to the doctor every four months, as the three-year anniversary of his diagnosis approaches in May. Soon the visits will be every six months, and then every year. He knows they will never stop, the appointments and the worry about his cancer recurring, the fraught drives to the doctor’s office.

For the moment, though, that’s hardly the focus. It’s about the football this week, even after that tweet, even after Herzlich found himself a focus of media attention, though he’s not the only cancer survivor on the Giants and Patriots rosters, with New England offensive lineman Marcus Cannon having returned this season from non-Hodgkin’s lymphoma.

The football is why Herzlich is here, why he got himself healthy enough to get back on the field, why he chose radiation, to give himself the chance to return. It hasn’t always been easy in this his rookie season, with the linebacker missing the final seven games of the regular season after suffering an ankle injury against the Saints on Nov. 28.

“It was a risk to come back in the first place,’’ Herzlich said. “We didn’t really know how my leg was going to hold up to different hits, or if it was going to break or if it wasn’t going to break. It was a risk.

“This is something I love. This is something that is a part of me. This is a chance I want to take.’’

He wanted to come back to BC. He wanted to come back to football. He wasn’t thinking about anything more. He certainly wasn’t thinking about the Super Bowl. And yet it hit him, coming off that plane, that he was here, that he had made it, that, as McGovern said, he was having his “Hollywood ending.’’

“This is a dream,’’ Herzlich said, “that I never thought would come true.’’

Amalie Benjamin can be reached at abenjamin@globe.com. Follow her on Twitter @amaliebenjamin.