U.S. Olympic tennis team

Serena Williams
Williams, 30, is making her third appearance at the Olympics. She has won 14 Grand Slam singles titles, including five at Wimbledon. Williams went two years without a Grand Slam title as she battled various injuries, but she enters the Olympics on a roll as the 2012 Wimbledon singles champion. (Photo by Paul Gilham/Getty Images)

Venus Williams
In 2011, Williams, 32, learned that she had Sjögren's syndrome, an autoimmune disease which can cause fatigue. Her ranking plummeted as she stopped competing due to the disease, but for 2012, she set making the Olympics as her top priority. Williams worked all year to rise high enough in the rankings to qualify and will be the first U.S. tennis player to compete in four Olympics. She won the gold medal in singles in 2000 and has seven Grand Slam titles, five of them at Wimbledon. (Photo by Paul Gilham/Getty Images)

Christina McHale
London will be the first Olympics for McHale, 20. She won the bronze medal in singles and silver medal in doubles at the 2011 Pan American Games. (Photo by Clive Rose/Getty Images)

Varvara Lepchenko
Lepchenko was born in Uzbekistan, but received political asylum from the U.S. in 2001. She changed her nationality and began representing the U.S. in 2007, though she only officially became a citizen in September 2011. This will be her first Olympics. (Photo by Clive Rose/Getty Images)

Liezel Huber and Lisa Raymond
This is the second Olympics for Raymond (right), 38, but the third for Huber, 35, who represented the U.S. in doubles in 2008 and her native South Africa at the 2000 Games. Huber and Raymond are the top-ranked women’s doubles team. (Photo by Kiyoshi Ota/Getty Images)

Williams sisters
The Williams are undefeated in Olympic doubles play, winning the gold at the 2000 and 2008 Games. They also have 13 Grand Slam doubles title, five of them at Wimbledon. Here, they celebrate the most recent of their doubles titles, won on July 7 at Wimbledon's All-England Club. (Photo by Paul Gilham/Getty Images)

Andy Roddick
Roddick, 29, will return to the Olympics after his debut in 2004. He reached the quarterfinals in singles. Roddick won the U.S. Open in 2003 and more recently captured the Eastbourne Championships on June 23. (Photo by Clive Brunskill/Getty Images)

Ryan Harrison
London will be the Olympic debut for Harrison, 20. He entered the ATP World Tour Top 50 for the first time in June. (Photo by Paul Gilham/Getty Images)

Donald Young
Young, 22, is going to his first Olympic Games. In February 2012 he reached a career-high No. 38 on the ATP World Tour rankings. In 2007, he won the boys’ singles titles at Wimbledon. (Photo by Clive Brunskill/Getty Images)

Mixed doubles is making a re-appearance at the Olympics after an 88-year absence. While the teams haven't been named yet, they will be formed from the pool of players on the U.S. team. One possible matchup could be Lisa Raymond (left) and Mike Bryan, who won the 2012 Wimbledon mixed doubles title on July 8. (Photo by Julian Finney/Getty Images)