Jason Miller can't walk. His right elbow bends only 80 degrees. His left arm doesn't bend at all.

He was born with osteogenesis imperfecta -- better known as brittle bone disease, which doesn't sound like a condition that lends itself to competitive tennis.

But Miller is strong. He's powerful. He has exceptional hand-eye coordination, too, honed for years in wheelchair basketball and softball.

And now, nine months after rolling onto the court for the first time, the Green Bay resident is convinced he can become the best "quad" tennis player in the world.

Don't take Miller's word for it, though.

Take it from one of his doubles partners, Aaron Powless, who says, "He can do it, and he knows he can do it."

Take it from his instructor, longtime wheelchair tennis coach Jackie Egelhoff, who calls Miller "extraordinary."

Or just take it from the No. 1-ranked wheelchair tennis player in the country, two-time Paralympian Jon Rydberg.

"He's got all the talent in the world," Rydberg said in a recent phone call. "He's a natural athlete. He's definitely still learning, but he's got a solid, solid base compared to most people that have only been playing nine months."

At age 33, Miller knows he doesn't have forever to prove people right. He's focused on making the U.S. team for the 2012 Paralympics in London.

The question is, can Miller make enough progress in so little time -- and can his body handle it?

The athlete

Miller's past suggests he's capable of a lot of things.

His condition wasn't diagnosed until he was 3 months old. He was going to the doctor repeatedly with broken bones, raising suspicions from social services that he might be a victim of abuse.

In reality, Miller had a defective chromosome -- a rarity for his condition, which most often is passed down genetically.

He was wheelchair-bound from age 12, when he became too big for family members to carry around. But his single mother never forgot the advice of the doctor who diagnosed him:

Treat your son as if he doesn't have the disease, because no matter what, the bones are going to break.

So, Miller started playing sports -- and he got stronger.

By the time he graduated from West De Pere High School in 1994, he had earned a wheelchair basketball scholarship to Southwest State in Minnesota. He took up weight training, transferred to the University of Wisconsin-Whitewater and won a national championship in basketball in 1999.

Then, Miller took up softball and won a national championship with the St. Paul Saints in 2006.

"Every doctor I've ever had," Miller said recently, during a break from practice at Appleton East High School, "has at first (asked), 'If you hit the ball, isn't that going to break your arm?' 'Well, it hasn't so far.'

"It's been weird, because I haven't really looked at myself as somebody with that disability. I've just been a guy in a wheelchair who's trying to be good at sports."

The disease

There is risk, though.

In addition to osteogenesis imperfecta, Miller has hypercallus bone formation, which contributed to the bone-cancer scare that forced him to drop out of Southwest State.

If Miller puts enough stress on his bones to cause even a hairline fracture, a massive amount of bone would grow around the area.

So, every day Miller swings a racquet puts him a step closer to breaking his right elbow, the good one. And Miller is acutely aware of how hard life would be if both his arms go.

He has a wife of seven years, a 6-year-old son and two adopted twins from Ethiopia. He produces a midday show for a Green Bay radio station. He has enough strength in his legs to drive and transfer himself from his regular chair to the one he uses for sports.

In one instant, everything he's worked 33 years to master with his disability could become a chore to learn all over again. Continuing to play sports might prove impossible.

But Miller forces himself not to think about that. Instead, he thinks about the Paralympics, about representing his country, about winning a medal. And it all sounds oddly reasonable for a guy who endured years of needling about why he wouldn't give the game a try before he even picked up a racquet.

"It's just kind of exploding into something that I really wasn't anticipating," Miller said. "It went from absolutely no expectations whatsoever to now, people in the wheelchair tennis community are talking about me being the best quad player in the world.

"It's like, 'Whoa.'"

The game

In April, International Tennis Federation physicians certified Miller as a "quad" based on the limitations of his upper extremities.

Watching him on the court, though, it's difficult to perceive that Miller is operating without much help from either elbow.

He moves with power and can turn on a dime, using both hands to propel himself and mostly his left to steer. His strokes are consistent, his serve hard with a touch of spin.

If Miller has a physical weakness, it's his mobility. But Egelhoff -- who previously coached the country's No. 1 women's wheelchair player, Kaitlyn Verfuerth -- said even that is "really good" compared to most quads.

"When I hit with him," Egelhoff said, "I'm forgetting that he is a quad, because he is so unusually good."

In his first tournament, October's Midwest Team Cup in Aurora, Ill., Miller placed second in the quad division and first in the men's "C" division. Most recent, he went to the IPFW Open in Indiana, and there weren't enough entrants to have a quad division -- so Miller entered the men's "B" flight, won the doubles bracket and placed second in singles.

He's competing against able-bodied tennis players, too, with the Fox Valley Warriors in Appleton. Based on Egelhoff's research, Miller is the first wheelchair athlete to participate in an able-bodied league in the state, and the first quad to do so in the region. The only rule change is that Miller gets two bounces.

Making the U.S. Paralympics team is in essence a three-year process -- one year to get nationally ranked, one year to push the ranking high enough to get seeded in the "open divisions" and one year to rack up enough points to be selected.

So, Miller doesn't have long to gain that extra mobility. Doesn't have long to perfect the shots. Doesn't have long to harness the emotions that so often have him talking to himself on the court.

But Miller is strong. He's resolute. Others think three years just might be enough, too.

Take it from Rydberg, who says, "If he plays the right tournaments and keeps training a lot every week, he can definitely do it."

Take it from Egelhoff, who says, "It's a high goal, but not out of his reach."

Or just take it from Miller himself, who says he hasn't given any thought to what he might try next if he actually pulls this off -- actually becomes the best in the world.

"It's a big enough goal," Miller said, "where I think having one goal is enough."

-- Tom Pelissero is assistant sports editor of the Press-Gazette. E-mail him at tpelisse@greenbaypressgazette.com