Murray out of Davis Cup

The world number 12, who suffered a disappointing first-round exit to unseeded finalist Jo-Wilfried Tsonga at the recent Australian Open, told his personal website that he did not want to risk further injury to the joint.

"Following the intensive off-season training, my right knee - which has a bipartite patella - started to act up again when I returned from Australia," he said.

"We had a scan done this week. Following discussions with my team, we have decided that it is better not to play in the Davis Cup tie against Argentina.

"I am very disappointed not to be joining my Davis Cup team-mates in Buenos Aires because I love playing for my country and have always enjoyed the team atmosphere of the Davis Cup."

Murray added that he is more cautious now after the problems he suffered with his wrist in 2007, which ruled him out of both the French Open and Wimbledon.

"Last year was very difficult with my wrist injury," he continued. "I learned about the importance of looking after my body and I don't want to make any mistakes going forward.

"Taking this preventive measure is a very difficult decision because I didn't play a full year last year.

"The next two months are very important if I am to maintain my chances of challenging the top players."

Murray broke into the top 10 in the ATP rankings at the beginning of the year with victory in the Qatar Open, only to slide out again with his loss to Frenchman Tsonga in Melbourne.

Murray's fitness trainer Jez Green explained more about his client's problem.

"Andy's workload in the off-season was incredibly high and put a lot of stress on the right knee," he said. "This is causing him some problems on certain movements.

"Changing surfaces three times in such a short time span would be a great risk to further injury."