, but found he was struggling . `` On Wednesday I could n't get up anymore - and the next day I just was n't in shape at all , '' he said . `` It 's a lung infection -- it 's the first time I 've had it - breathing is difficult -- I feel I am not fine , I 'm still very tired and slow . `` The doctors say it 's too serious for me to try -- and that I should rest for at least two weeks -- obviously I ca n't take any more chances . '' Federer , who has a home in Dubai , was looking to regain his title from Novak Djokovic , who will now be top seed , with Murray also in the field for his first tournament since Australia . Czech Jan Hernych , who went out in the final round of qualifying , benefits from Federer 's withdrawal to go into the main draw . In men 's ATP action on Sunday , Sam Querrey beat fellow American John Isner in the final of the tournament in Memphis . Eighth seed Querrey , who had accounted
-LRB- CNN -RRB- -- World number one Roger Federer is suffering from a lung infection and has pulled out of this week 's $ 2 million ATP tournament in Dubai . Australian Open champion Federer is set to be sidelined for up to six weeks and may not return to action until a big hard court event in the United States in March . Federer , who won his 16th grand slam when beating Britain 's Andy Murray in Melbourne , has been advised by a doctor not to play for at least a fortnight . He is set to play at the Masters Series event at Indian Wells which starts on March 11 , but may have to wait until the following tournament in Miami . `` There are no guarantees that I will play at Indian Wells -- this could be a maximum of six weeks , but if it 's treated properly everything should be fine and I should be back fairly quickly , '' he told the official ATP Tour Web site . Federer , who is a four-time Dubai Open champion , had traveled to the United Arab Emirates to practice ahead of the tournament