New York, 20 October 2010 | AP

Serena Williams is officially done for 2010, joining sister Venus on the sidelines for the remainder of the WTA season.

In a statement e-mailed to the AP by her agent, Williams said she had “re-tore the tendon” in her right foot, which she originally injured by cutting it on glass at a restaurant shortly after winning Wimbledon in July.

Williams had surgery in New York on Monday, after first first having the foot repaired July 15.

Her announcement comes less than two weeks after Venus Williams said she would not play for the rest of the year because of a lingering injury to her left knee.

Both sisters will miss the WTA Championships next week in Doha, Qatar, and the Fed Cup final between the US and Italy next month at San Diego.

Serena hasn’t played on tour since beating Vera Zvonareva 6-3 6-2 to win her fourth Wimbledon championship and 13th Grand Slam singles title overall, the most among active women.

The American cut her right foot on glass at a restaurant while she was in Munich after her victory at the All England Club, but she went ahead and played in an exhibition match July 8 in Brussels against Kim Clijsters that drew a tennis-record crowd of more than 35,000.

A week later, Serena had an operation on the foot in Los Angeles.

After withdrawing from the US Open, she returned to practice in September, but then put off her comeback by pulling out of tournaments in Tokyo, Beijing and Linz, Austria.

On October 10, in a posting on her official website, Serena said she “re-strained” her foot by overtraining and “likely” would be out of the year.

Her statement Tuesday said: “It is with deep frustration that I am withdrawing from the WTA Championships at Doha and the Fed Cup Final. Pushed by my desire to return to competition, I trained too hard too soon and re-tore the tendon in my foot. As a result, yesterday morning I had to have another procedure to repair it. I thank everyone for their continued support during this difficult time and look forward with strength and determination to getting back on the court.”

Earlier this year, Williams missed all of February, March and April because of a left knee problem.

She closes 2010 having participated in only six singles tournaments, going 25-4 with two titles – at the Australian Open and Wimbledon.

She lost the No.1 ranking last week to Denmark’s Caroline Wozniacki, who has yet to win a Grand Slam tournament.

In August, both Williams sisters told the US Tennis Association they planned to play against Italy in the November 6-7 Fed Cup final on an indoor hard court at the San Diego Sports Arena.

Neither Williams has competed for the US Fed Cup team since 2007.