TAMPA, Fla. — Rick Burkholder answered the question no one wants to ask when the subject is cancer.

"Nobody is giving us any numbers — 'You've got this much time' — or anything like that," Burkholder, the Eagles' trainer, said Thursday. "Everything has been positive in terms of treating this cancer."

The cancer first showed up on Jim Johnson in 2001. He had the melanoma on his skin removed, and for seven years of follow-up exams, there was no sign of its return. There was every reason to believe the wily old defensive coordinator had beaten the disease.

But there is no defense against this thing, no scheme or game plan that can stop the growth of tiny cells into something terrible.

Early this month, as the Philadelphia Eagles prepared for their wild-card playoff game in Minnesota, Johnson experienced sharp pains in his back. For a 67-year-old who played football for years, that's not out of the ordinary enough to ring alarm bells.

"We started treatments for back pain," said Burkholder via telephone from San Francisco. He and his family were changing planes on the way to Honolulu for the Pro Bowl.

The back pain became a subplot during the Eagles' three-week run through the playoffs. Johnson wasn't able to coach from the sideline, as he normally does, and sat up on the press-box level. He was using a cane to walk and getting ferried around on the carts they use to transport injured players from the field.

After the Eagles' defense played brilliantly in a victory over the Giants on Jan. 11, coach Andy Reid joked about Johnson being "100 years old" and coaching from the press box like Joe Paterno. He also described his top assistant coach of 10 years as the "best defensive coordinator in football."

Reid's good-humored ribbing reflects what he and everyone else believed was going on with Johnson. After the Giants game, Johnson underwent an MRI exam to find the source of the continuing pain.

"We thought he was going to have a disk problem," Burkholder said.

The MRI showed a tumor on Johnson's spine, a metastasized melanoma that formed years after the original skin cancer had been removed. That was the source of the pain. But the more serious concern is that cancer has spread to other areas. Burkholder declined to give specifics, which is understandable, but the concern in his voice was clear even from 3,000 miles away.

Your first reaction is concern for Johnson, his future and his family. The second is awe at the pain he must have endured to put together defensive plans for three playoff games. Then comes a keen appreciation for a man who seldom seeks any attention at all.

The word from the Eagles is that Johnson plans to continue coaching. That comes as no surprise. He is the very definition of the phrase "football lifer."

Johnson played quarterback in college and tight end in an injury-shortened NFL career. He has the stiff-legged gait of those old football men who left their knee ligaments on some half-remembered field in the days before MRIs and arthroscopic surgery. He went into coaching, starting off as a head coach at Missouri Southern.

Pretty soon he had developed a taste for coaching the defensive side of the ball. Having played quarterback, he delighted in playing with the minds of quarterbacks — creating blitzes and pass-coverage schemes that confused and intimidated them.

His career took him to Notre Dame and Phoenix, Seattle and Indianapolis and finally to Philadelphia. He was in position for a head coaching job here and there but never got another chance. By the time the Eagles were going deep into the playoffs every season, Johnson's age was working against him.

One suspects his greatest liability in that regard has been what is normally a virtue. Johnson is possessed of an honesty and forthrightness that is scarcely found in football coaches. In a culture where the governing principle is the less said, the better, Johnson's candor is especially refreshing.

It comes down to the fact that Johnson is too good at his job and too comfortable with himself to bother covering up or misleading reporters and fans. He saves all his deception for his defensive schemes.

In his 10 seasons with the Eagles, Johnson developed a dominating defense not once, but twice. The unit that carried the Eagles to the brink of this year's Super Bowl bore little resemblance to the defense that played against the Patriots in February 2005.

That young defense is one of the best reasons to be optimistic about the Eagles' chances to deliver that elusive championship in the next year or two.

Here is one very fervent and heartfelt wish: that Jim Johnson is on the sideline, shouting and coaching and cancer-free, for as long as he wants to be.