Chronic back pains forced the American crowd-favourite to withdraw from the next week's Cincinnati Masters, tournament officials said on Saturday.
Novak Djokovic has parted company with coach Radek Stepanek days after the departure of head coach Andre Agassi from his team, the former world number one announced on Wednesday.
But Agassi, who began working with Djokovic at the French Open last month, says Djokovic is motivated to do the hard work required now, rather than later.
It was his first tournament win since January and has left the world number four confident of mounting a challenge at Wimbledon, where he has been drawn against Slovakia's Martin Klizan in the first round.
The American former champion has decided to skip French Open in 2006
Andre Agassi and Andy Roddick polished their culinary skills at the Dacor Taste Of Tennis party in New York
Martina Navratilova is set to retire just a month short of her 50th birthday.
No official reason was given for Andre Agassi pulling out of the Canadian Open.
Andre Agassi lost 6-4, 6-3 to Italian qualifier Andrea Stoppini in the Legg Mason Tennis Classic second round.
Novak Djokovic claimed his sixth Australian Open title on Sunday as the 28-year-old continues to dominate men's tennis. Here are some of the key statistics for the all-conquering Serb.
Andre Agassi will begin an emotional farewell appearance at Wimbledon against little-known Serbian Boris Pashanski in the first round on Tuesday.
The Serb beat Guiilermo Canas 6-3, 6-2, 6-4 in the final of the Miami Masters on Sunday.
Agassi said in a statement that it was a regrettable decision and he would miss playing in the tournament.
"There have been moments for optimism - plenty. And on the men's side, not as much."
Look who we spotted at the Flushing Meadows this year.
Roger Federer added yet another record to his vast collection when he guaranteed becoming the oldest ATP world number one by beating Dutchman Robin Haase 4-6, 6-1, 6-1 to reach the semi-finals in Rotterdam on Friday.
The Swiss top seed lived up to his billing as the world's best player to reach the semi-finals at the Australian Open.
Roger Federer believes that criticism from tournament organisers of a spate of pullouts at the year-ending Masters Cup was fully justified
Andre Agassi and Rafael Nadal pulled out of the season-ending Masters Cup on Monday
Federer is chasing a third consecutive finale title -- a feat last achieved by Ivan Lendl in 1985-87.
"As I begin the next chapter of my life, I am looking for ways to pursue a career in business, specifically in real estate," Agassi, 36, said in a statement.
Defending champion Roger Federer was drawn against Guillermo Coria, Ivan Ljubicic and David Nalbandian in the group stages of the Masters Cup.
The organisers of European Masters Series tournaments will meet in Paris on Tuesday to discuss ways to curb the number of withdrawals by leading players.
Andre Agassi continued to defy the odds and elude retirement by shocking eighth seed Marcos Baghdatis in a five-set thriller.
Andre Agassi has had another injection in his troublesome back before his clash against Marcos Baghdatis.
Andre Agassi's farewell party begins on Monday with a lingering question: how long will the celebration last?
Andy Murray passed his first test under new coach Brad Gilbert, beating Ramon Delgado 6-4, 6-3 in the second round.
Brad Gilbert has agreed to coach Andy Murray and assist the LTA with its performance programmes.
Agassi, who has not seen action since a third-round loss to Rafael Nadal at Wimbledon, is seeking a fifth title in Los Angeles.
Britain's Andy Murray has said he wants American tennis guru Brad Gilbert to be the coach to take him to the next level.
Andre Agassi scored a 6-4, 7-6, 6-4 win over Italian Andreas Seppi in the second round
Andre Agassi said on Saturday he would retire from tennis after this year's US Open.
Tim Henman beat Andre Agassi in the first round of the Stella Artois Championships