At 15, you're supposed to be preparing for high school, learning to drive, starting to date.

You're not supposed to be dealing with bladder cancer and a subsequent disease that puts you in Children's Hospital for the holidays.

But A.J. Oster is.

You should be playing basketball like another teenager, Ari Grashin, hanging out with your buddies, enjoying adolescence.

One day a month ago, Grashin lost his coordination. The family hoped it was just an inner ear infection until a doctor told them it was something else, something worse: a brain tumor.

Suddenly he is at Children's too.

On Sunday, so were many tall men in red-and-white Santa hats. On another winter day from their past, Oster and Grashin might have been talking about the Sonics. Now they were talking to them.

"Hey, what's up buddy, how you doin'?" Gary Payton says to Grashin, approaching for an autograph.

In the next half-hour, Payton is upstairs in Oster's room, laughing and joking, impressed by Oster's Nintendo Game Cube and the youngster himself.

For every drug bust and felony charge and negative perception of professional athletes, there are days like these, unnoticed days, when the athletically gifted and highly paid prove they are also human beings.

"They really have a tender side as well, a loving, caring side," said Michelle McMillan, wife of Sonics coach Nate McMillan.

Every Sonics player visited Children's aside from Vladimir Radmanovic, who suffered a concussion Saturday night in the victory over Detroit and nearly went to a hospital for different reasons.

They first mingled with patients in the "Train" lobby. Jerome James held a 3 1/2-month-old infant who has been vomiting frequently and troubled by urinary tract infections. He rocked her back and forth and talked baby talk to the little girl with an I.V. sticking out of her right hand.

Art Long, who looks intimidating and conveys all things tough, gently picked up a little boy and gave him a stuffed dog.

"He named him Jolly," Long said. "That's a good name."

From there, the Sonics took elevator rides to see the more seriously afflicted, the ones who may lead carefree lives someday or never leave their rooms again.

A girl in one of the wards the Sonics visited was not expected to make it through the night. Payton knows what that's like.

"I was staying in touch with three of them," Payton said. "Two of them died on me. I was here holding their hand when they died. It's been an up-and-down experience for me."

This is a drastically different side of Payton, a player known for his rugged style of play and confrontational behavior. This is where the spotlight shines on him in a private place, where the feisty point guard replaces ferocity with generosity, warming hearts instead of ripping them out.

"It means a great deal to me," Payton said. "These kids idolize us. Hopefully we can help some of them."

Payton donates money to Children's in the names of the two patients who died in his presence. On Sunday, he gave his time, leading a group of players from one room to another, a point guard doing what he usually does, getting everyone involved.

Brent Barry met a teenager with a bloated stomach caused by an undetermined disease, calling him "my kind of kid."

"He's a big Sonics fan," Barry said. "He was talking to Nate about plays he should be running."

James met a 5-year-old with cancer and it really hit home: James is the father of a 5-year-old.

"I had to stop and thank God for keeping my family healthy," said James, who also prayed for his new acquaintances.

The Sonics were there to distribute joy and happiness, eliciting smiles, facilitating hope. But they sounded like recipients of something called perspective.

"Those kids have the strongest attitudes," reserve guard Earl Watson said. "They are stronger than I could ever be. If I had children with those attitudes, I'd be the happiest father in the world."

"As much as we gave them, they gave us more," said Barry, whose head was down upon departure, his expression mixed with sadness and gratefulness.

He saw a 2-week-old baby who just had open heart surgery. He has a 15-month-old son at home. His head wasn't shaking, but his mind was, realizing it could be his boy in intensive care instead of someone else's.

"One day you wake up and your son's here," Barry said. "The day before, he's in the back yard playing on the swing."

Oster is evidence of that. In eighth grade, he was diagnosed with bladder cancer and underwent extensive chemotherapy, missing a year of school.

Everything was fine in ninth grade: Oster was playing baseball and being a normal kid again. His family was in Athol, Idaho, north of Coeur d'Alene, living in the country like they always wanted to.

One day last summer his mom was on the deck telling his dad, "life is so perfect right now," and the next, their son was back in a doctor's office for a routine checkup, hearing that he has a pre-leukemia condition and is in need of a bone-marrow transplant.

On Sept. 11, while the rest of the world was shocked, the Osters rejoiced when the phone rang and a doctor told them that sister Tara, 12, was a perfect bone marrow match.

On Dec. 13, the transplant took place and, nearly two weeks later, the prognosis is good.

Grashin is also recovering. His brain tumor was removed last Friday, a day after Sonics owner Howard Schultz and forward Desmond Mason visited and had cookies and milk with him.

On Sunday, Payton was giving Grashin a hard time for having a purple-and-gold Lakers ball for him to sign. Clearly a big hoops fan, Grashin was wearing a basketball-designed yarmulke.

All of the students at Northwest Yeshiva High School on Mercer Island fasted on Friday in tribute to Grashin.

Two days later, Grashin's family was waiting for the answer to the benign-or-malignant question when the Sonics arrived and discovered that those losses to the Heat and the Clippers were more meaningless than they thought.

"These kids give us hope in the human spirit," said assistant coach Dean Demopoulos. "It's reciprocal. We learn our lessons from them."