The England batsman admits he is keeping his 'fingers crossed' he will be involved in the Ashes this summer after being ruled out of the series against New Zealand next month.
Kevin Pietersen to miss New Zealand series as he looks to recover from injury before Ashes
Pietersen injured his right knee during fielding practice in the away series in New Zealand last month and was unable to play in the third and final test.
The batsman suffered "significant bone bruising" to his right knee and will have a scan next week to determine when he is able to resume training.
"Kevin Pietersen has been ruled out of the upcoming test series against New Zealand as he continues his recovery from significant bone bruising to his right knee," a statement said.
"He will have a repeat scan next week to determine when he is able to resume training."
The injury also meant Pietersen was ruled out of the Indian Premier League.
Pietersen tweeted: "Injuries are a sportsman's worst nightmare! This one is hurting me the most.."
In response to supportive messages he received on the social networking site, Pietersen wrote he was "trying" to be fit for the Ashes series and that he had his "fingers crossed".
England, who face home and away Ashes series against Australia this year, face New Zealand at Lord's starting on May 16 before the second test starting on May 24 in Leeds.
All three test matches in New Zealand ended in draws.
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