At about this time last spring, Boston College outside linebacker Mark Herzlich was facing a far weightier opponent than any of the offensive lineman he faced while earning Atlantic Coast Conference defensive player of the year honors in 2008.

In May 2009, Herzlich was diagnosed with a rare bone disease called Ewing's sarcoma.

On Thursday, the 22-year-old Conestoga High graduate was back at Pennsylvania Hospital as the keynote speaker at the hospital's 2010 Survivors Day ceremony.

In the hospital where he underwent radiation and chemotherapy treatments, and before a crowd of 300 other cancer survivors, family members, physicians and staff, Herzlich went to the microphone looking as if he had just left a health spa.

In November, he was determined to be in remission, with a 99 percent chance that the cancer was gone.

"To people in this room, you know what it is to be a cancer survivor," Herzlich said during his 10-minute speech. He said he was told "they don't know if you have a 70 percent chance of survival or a 10 percent chance of survival, not knowing if I was going to survive to the football season. I was lucky enough to get through it. When I got that biopsy back and they said, 'We can't find any cancer,' that's where we wanted to get to."

A 6-foot-4, 238-pound NFL prospect from Wayne, Herzlich was forced by his illness to sit out the 2009 season. He was granted a medical redshirt by the NCAA and will be back on the field this fall as redshirt senior.

"It obviously was a long wait," said Herzlich, who is fully participating in the Eagles' off-season conditioning program. "I just want to keep progressing, and once I get through the first couple of games, it'll be business as usual. It's an interesting story, but at this point, it's all about wins."

Herzlich, who played in all 13 of BC's games as a freshman, moved into the starting lineup in 2007, then led the Eagles with 110 tackles and eight pass breakups in '08. His six interceptions tied him for the team high.

But last spring, a persistent pain in his left leg would not go away, and Herzlich and his family went to see the doctor. He had played the Eagles' spring game in late April and performed well. On May 12, 2009, Herzlich began treatment, which continued into the fall.

"He basically decided he was going to do what it takes to get better, and never questioned anything," said Dr. Arthur Staddon, the head of Pennsylvania Hospital's cancer program. "He had a great attitude. He didn't have any problems with the chemotherapy, no nausea or vomiting. Sometimes he'd have five days in a row, and at the end of the day, he'd go play golf."

When he couldn't suit up last season, Herzlich became a constant at the side of BC coach Frank Spaziani during Eagles games. Through meetings and correspondence, he also reached out to others who were dealing with similar health issues. And with Herzlich playing a big role, $200,000 was raised to benefit Uplifting Athletes, an organization that works with college athletes to raise awareness of rare diseases.

Now, although he will continue to share his experiences with cancer, Herzlich can move on to the next phase of his life. During BC's spring drills this year, he participated only in noncontact workouts. He expects to be ready to go all-out when preseason camp begins in August.

"I definitely still have dreams of playing in the NFL," he said. "But first things first, I have to get on the field and prove I can play."

Contact staff writer Kevin Tatum at 215-854-2583 or ktatum@phillynews.com.