Kevin Pietersen has been ruled out of the Champions Trophy following scans on his injured knee.

The England and Wales Cricket Board has confirmed Pietersen will miss the June tournament after a repeat MRI scan on the injury, which forced him home early from the recent tour of New Zealand, revealed only "some improvement" to bruising in the bone.

The assessment is set to create further concern over Pietersen's place for the start of the Ashes series, which begins at Trent Bridge on July 10.

"Kevin Pietersen has been ruled out of the ICC Champions Trophy following a repeat MRI scan on his right knee earlier today," the ECB statement read.

"The scan has shown some improvement in the bruising to the bone that occurred in the build up to the Test Series against New Zealand in February.

"However Pietersen will not have recovered sufficiently in time for the NatWest one-day series against New Zealand beginning May 31 and the ICC Champions Trophy which follows.

"Pietersen will now start a graduated rehabilitation program with a view to resuming full training by the middle of June."

That return date would leave Pietersen with just under a month to prepare for the start of the Ashes.

Pietersen's county side Surrey have two LV= County Championship games during the latter half of June, which could provide the right-hander with match practice before the Australia series.

But the decision is a setback to his return after team director Andy Flower had suggested, at the end of the New Zealand tour, that Pietersen would be fit for the entire English summer.