PERTH, Oct 21 AAP - England's form batsman Michael Vaughan will sit out his team's tour opener, but insists his knee injury will not stop him playing in the upcoming Ashes series starting next month.

The Yorkshireman enjoyed a remarkable northern summer in which he registered four Test centuries including scores of 195 and 197 against India.

But his right knee, which he had a minor operation on last month, has pulled up sore forcing him out of the match against an ACB Chairman's XI at Lilac Hill tomorrow.

His knee will be of an enormous concern for the England team as it already has some major injury worries in the 16-strong squad.

But the 27-year-old said he hoped to be fit in time for the two-day match against Western Australia starting at the WACA ground on Thursday.

Allrounder Andrew Flintoff and Darren Gough will also miss the Lilac Hill fixture as they try to recover from respective hernia and knee operations.

But Vaughan will arguably be the tourists' biggest concern as his partnership with Marcus Trescothick at the top of the order is seen as pivotal to England's hopes of winning an Ashes series for the first time in 16 years.

Vaughan has scored 1710 runs in 23 Tests and his average of 47.50 is easily the best in the England team.

The only other batsman with an average of more than 40 is Trescothick.

"A bit of dehydration from the flight and obviously a little bit of swelling (of the knee) but it has gone really well the past 48 hours," Vaughan said today.

The right-hander is one of the great unknowns for Australia as he missed the 2001 Ashes series also because of a knee injury.

Vaughan has only played one match against Australia in a one-day encounter at Old Trafford last year but was bowled first ball by quick Jason Gillespie.

"I have played one game so far and only lasted one ball, so things can only get better," he said.

And despite averaging an impressive 90 in six Tests over the northern summer he also conceded he was also dismissed first ball by Australian paceman Glenn McGrath in their only encounter in a county match.

However the amiable Vaughan didn't appear very concerned about his previous efforts against Australia's pace attack.

He said he and Trescothick would try to play in a positive fashion against McGrath who reached the 400 Test wicket mark in Sharjah today.

Vaughan said the openers probably wouldn't follow New Zealand's tactic against Australia last summer of leaving anything slightly outside of off stump.

"If it is there to leave you have got to leave it, but I think the positive approach is the best approach," he said.

"Marcus and I are the type of guys who go out looking to be positive.

"But Glenn McGrath is going to have periods of play where he's bowling very well and leaving the ball might be the best option.

"But we'll have to judge the wicket and the best way to play on the day."

The first Ashes Test starts on November 7 in Brisbane.

Meanwhile the ACB Chairman's XI made one change with West Australian batsman Chris Rogers replacing teammate Scott Meuleman who has a thigh injury.

The England team is: Nasser Hussain (c), Mark Butcher, Andrew Caddick, John Crawley, Richard Dawson, Ashley Giles, Matthew Hoggard, Stephen Harmison, Simon Jones, Robert Key, Alec Stewart, Marcus Trescothick, James Foster.

The ACB Chairman's XI is: Michael Hussey (c), Ryan Campbell(v-c), Michael Clark, Kade Harvey, Brad Hogg, Chris Rogers, Matthew Nicholson, Marcus North, Callum Thorp, Paul Wilson, Kim Hughes, David Hookes, Wayne Clark.

© 2002 AAP

This report does not necessarily represent the views of the Australian Cricket Board.