Tim Henman has revealed he has asked for a late start to his US Open campaign because of injury.
Henman is due to face Fernando Verdasco on Tuesday
The British number one has just overcome a stomach muscle problem but he has now been hit by the recurrence of a chronic back injury.
"My back has stiffened up over the last few days which is frustrating," said Henman, who faces Spain's Fernando Verdasco on Tuesday.
"I think my body compensated for the stomach injury, making my back stiff."
Henman has two degenerative discs in his back which cause it to stiffen up without warning, a problem he has struggled with for over a year.
"I haven't been able to practice as much as I would have wanted, but at least I know what the problem is and how to go about treating it," continued Henman on his personal website.
"It's not the best way to prepare but I have to simply try and take the positives out of the situation and try and deal with it the best I can.
"Hopefully by the time my first round match rolls around it'll be a bit better and I'll be able to focus solely on winning."
Henman has won just one match since going out of Wimbledon in the second round and will lose ranking points if he fails to match his performance in reaching the US Open semi-finals last year.