England's bowling coach David Saker has admitted that nobody can be certain if Kevin Pietersen will be available for this summer's Ashes.

The 32-year-old is currently recovering after he underwent surgery on a knee injury, which in turn ruled him out of the ongoing Test series against New Zealand as well as next month's Champions Trophy.

It had been claimed that the batsman would be available by the time that Australia visit, but Saker has conceded that his participation is still in the balance.

"I just asked him if he thought he would be all right, and he said he thinks he will," said Saker.

"It was probably the only answer he could give. He doesn't know and until he knows he can run around and it doesn't flare up he can't have an answer on that."

The first of five Tests between the two nations will get underway on Wednesday, July 10.