Nothing that comes Ryan Zimmerman's way on a baseball field can shake the Washington Nationals third baseman.

This is, after all, just baseball, a kid's game played by grown men. Zimmerman has seen much more serious things in his life, matters far more complicated than simple wins and losses accumulated over a 162-game season.

Zimmerman was just 13 years old, barely into his teens, when his mother, Cheryl, was diagnosed with multiple sclerosis, a chronic disease that attacks the central nervous system. The news changed her youngest son's life in a hurry.

"It made me and my brother grow up quicker," Zimmerman said. "We had to learn to do things around the house, stuff your mother usually does. We had to learn how to do our own laundry, learn how to cook. We had a little more responsibility in our lives.

"I'm not saying me and my brother were the only two people in the country who've had to cook and clean," he said, "but it opened up our eyes. It lets you know stuff's not guaranteed, and you take every day a little bit more seriously. When I have a bad day on the field, it puts things in perspective."

And he makes a mean pot of spaghetti.

Cheryl Zimmerman was an elementary school special education teacher, and for the first few years after her diagnosis, she continued to work. MS is like that, unpredictable in its impact from day to day and year to year. Then there was a boating accident in which she suffered a broken vertebra. Slowly after that, her condition deteriorated, and by 2000, she was in a wheelchair.

"When my mother was first diagnosed, it wasn't that bad for a while. Then, after the accident, it became more serious,'' he said. "It showed that you can't really take anything for granted. It made us mature a lot faster.

"My mother is tough. She's a strong person. She never let her disability bring us down. She still let us be kids and have fun."

Fun for Zimmerman was playing on a traveling high school team from Virginia Beach, Va., near Chesapeake Bay. His teammates included future Major Leaguers like David Wright, Michael Cuddyer, Mark Reynolds and B.J. Upton. "We were pretty good," he noted.

Zimmerman moved on to the University of Virginia, where he was a .355 hitter over three years, and the Nationals made him the fourth overall pick in the June 2005 First-Year Player Draft. The next year, he drove in 110 runs and was runner-up in the NL Rookie of the Year voting to Hanley Ramirez, the Florida Marlins' shortstop.

Now he's become the face of the Nationals, cementing his position by hitting a walk-off home run to win the first game in the team's new stadium in March. It was his fourth game-ending homer. He also is the team's all-time leader in hits, doubles, home runs, runs batted in and games played.

"He's talented and he's mature beyond his age," Washington manager Manny Acta said. "He's a special player."

After the 2006 season, Zimmerman started the ziMS Foundation to help pay for research and assistance for MS.

"We're in the third year with the foundation," Zimmerman said. "It's getting better every year. Our big thing is a November golf event. We raised $40,000 the first year, then $90,000 last year. We're planning more things, including a bowling event around the D.C. area."

In the meantime, he is one of baseball's rising young stars, a cornerstone for the Nationals and a player who has the game and his life in the proper perspective, thanks to a courageous mother who taught him how to face the curveballs that sometimes come along.

Hal Bock is a freelance writer based in New York.