Colin Gooley was not yet 10 when cancer forced him to undergo a rotationplasty to remove a tumor in his right leg. This operation took out the knee joint and turned the tibia around so that a prosthetic could be attached.

Denise Castelli broke her right leg sliding into second base during a college softball game in April 2008. The leg became infected and never fully healed. It was amputated in November 2009 and a prosthetic was attached.

But those injuries haven't ended their athletic lives. In fact, they might be more active than ever. Gooley, 17, and Castelli, 25, will be ball persons at this year's U.S. Open.

"I know it would mean a lot for the amputee community and the community of people with disabilities to show everyone that we're more than capable of doing things, even though it might be a little different," Castelli told The Star-Ledger.

Both went through two rounds of tryouts that started with more than 500 candidates. The field was reduced to 120, and then between 70 and 80 made the final cut, according to Tina Taps, the U.S. Open director of ball persons.

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Castelli, a New Jersey native, was an outfielder at the University of New Haven, and her softball skills helped during the tryouts.

"She's got a shotgun of an arm," Taps told The Star-Ledger. "She's fully capable of throwing the ball the full length of the tennis court."

Gooley skis, snowboards and plays varsity lacrosse for Baldwinsville High School in upstate New York, even though the rotationplasty makes it look like, in the words of his doctor, "you have a foot coming out of your thigh."

"I don't know what he doesn't do," said Erik Schaffer, president of A Step Ahead Prosthetics & Orthothics. "He lives a life without limitations."

Ball persons are the unsung heroes of the U.S. Open. They sit by the net or baseline and chase down tennis balls between rallies. The position requires speed, coordination and quick thinking. It isn't glamorous and they are only really noticed if something goes wrong. But they are necessary to ensure the tournament runs smoothly. Ball persons must be at least 14 and earn $7.75 an hour for their duties.

Look for Gooley and Castelli at the 3:36 mark in the video below. "We want to teach the average person that disabled people can do anything able-bodied people can do," Gooley said.