Michael Vaughan is continuing the rehabilitation process on his injured knee under the supervision of Yorkshire physiotherapist, Scott McAllister, but it is not yet known if he will be fit for the start of the new season.

McAllister is keeping the England management informed but Vaughan is still strengthening his knee and has not yet held a bat.

"We will probably know in about two weeks just when Michael will be able to start playing again," said Yorkshire's director of cricket, David Byas.

The likelihood is that the England captain will make his comeback with Yorkshire, but as a centrally contracted player that decision is up to England boss, Duncan Fletcher.

When England emerged triumphant from the Ashes series last September, Vaughan's position as captain and one of their top batsmen seemed secure for years to come, but the situation has changed a lot.

Vaughan's damaged knee caused him to cut short his time in Pakistan then forced him to return from India without playing in a Test.

Andrew Flintoff took over as captain and he was named man-of-the-match and the series when England triumphed over India to level the series.

Alastair Cook and Owais Shah have both exceeded all expectations with the bat and with these and other players coming up through the county system, Vaughan now also needs to score runs consistently.