"It was a roller coaster," Wilhelm said.

By the time the wheels stopped spinning, last year's Chargers were 1-3 and Wilhelm wondered about his life as a starter.

After biding his time as a backup and on special teams, Wilhelm was a first-teamer last year.

But a strained calf interrupted his opening month, forcing him to miss nearly three games -- the Chargers went 0-3.

"With my injury and the team being down, I was down," Wilhelm said. "I felt I could help but I couldn't come back. That wasn't fun."

The good times were to come -- save that bruising afternoon in Minnesota when Adrian Peterson set the NFL rushing record.

"After that hiccup in Minnesota, from there on we were on a roll, myself included," the 6-foot-4, 245-pound Wilhelm said. "We started to zone in and understand each other as a defense and that was what gave us great success."

The Chargers are expected to be great again this year and make a beeline for Tampa, Fla., and the Super Bowl.

If so, Wilhelm will be front-and-center.

"He is a tremendous athlete," said veteran Carlos Polk, Wilhelm's backup. "And he's more comfortable in there.

"That first year starting he was thinking and learning what he should do. Now he knows what he is doing and learning what offenses throw at him. He's a very smart player, as well as being a good athlete."

Wilhelm was oh-so-good -- despite missing nearly three games -- to finish second among Chargers with 144 tackles, with three interceptions and a sack.

But what Wilhelm, a six-year pro, holds dear is the experience. The knowledge that comes with being a starter and what is expected over a demanding season that tests a man's body and soul.

"I understand now what it takes to be a professional," he said. "I thought I knew, but it's the week in, week out rigors you deal with mentally and physically that are ever-changing. And it's something you need to quickly adapt to."

CAMP CALENDAR: Team breaks training camp on Aug. 23.