England will not panic over potential injury scares to their two most influential players in the build-up to the ICC World T20.

All-rounder Andrew Flintoff has already admitted his rehabilitation from recent knee surgery, which he injured while playing in the Indian Premier League, is behind schedule and remains doubtful for England's opening match against Holland at Lord's on June 4.

He has now been joined on the sidelines by influential batsman Kevin Pietersen, who has been ruled out of the NatWest one-day series against West Indies with an Achilles problem which England hope he will recover from with 10 days rest.

Neither player was missed in the opening match of the One-day series when the £600,000 Headingley drainage system failed to cope with torrential early morning rain and prompted the match to be abandoned in bright sunshine by mid-afternoon.

But their absence could be felt in the next two matches of the series, which continues at Bristol on Sunday, as England attempt to build some momentum to take into the World Twenty20 event.

"It's not an ideal situation, but any time you get injuries is not an ideal situation," conceded captain Andrew Strauss.

"It's so hard to second guess whether Fred would have been injured anyway, you just don't know.

"Thankfully there is still plenty of time before the Ashes and I think we fully expect KP (Pietersen) to be ready in 10 days or so - there's no need to panic just yet injury-wise, it's something we can manage."

Despite Strauss' philosophical response to losing his two key players, with such a big summer ahead England would prefer for both of them to be fit and playing in the build-up to the World Twenty and the Ashes.

"Pietersen not really a concern"

Pietersen is less of a worry after feeling the injury during the second Test triumph in Durham, but his loss would be a major blow to England's ambitions of competing in the Icc World Twenty20 should his injury prove more troublesome than first diagnosed.

"His injury is not really a concern," stressed Strauss.

"It flared up in Durham and he was feeling pretty sore coming here this week, but the medical staff feel that 10 days rest will do him the world of good so hopefully after that period he should recover to quite a large extent.

"The first time he mentioned it was in the West Indies but is very manageable and something that wasn't a big issue and it was only last week in Durham that it really flared up, so why that happened we don't really know."

New duo doing good

Although Pietersen played in the two-Test series rout of West Indies, he is yet to play a significant innings this summer while Flintoff's absence has been covered by the superb contributions of Graham Onions and Tim Bresnan.

Yorkshire all-rounder Bresnan was set to continue his run in the England team for the opening one-day international until the match was washed out and Strauss believes England can make a massive stride forward as a squad if they can continue their winning run without their two biggest stars.

"I don't think the fact they are not playing right now is a cause for concern," he claimed.

"The guys who came in and played in the two match series played well and that's encouraging rather than something to be concerned about.

"The T20 is not something I'm involved with, but there are quite a few of the Ashes squad involved in that and if we can get more wins under the belt that will really help us.

"If we can get some more wins under our belt in that tournament in our own conditions then I think we have a really good chance of doing well in that tournament."

Before Strauss takes a break from international cricket while that tournament is being staged - he withdrew from selection for it - England must first attempt to overcome West Indies in the remaining two One-day Internationals.

Morgan to be called

Uncapped Middlesex batsman Eoin Morgan is tipped to be given his debut in Bristol as a replacement for Pietersen, particularly as he has been selected for the World Twenty20 squad, but Strauss insisted they would not look ahead to that tournament when they consider selection for the next two matches.

"I think it's important to compartmentalise each form of the game and pick the best side to play in any given series," said Strauss.

"We gained some momentum in one-day cricket in the West Indies - we were a little bit Jekyll and Hyde up and down but we came through and won the series and we need two more matches to develop something for the One-day squad.

"Then it goes to the T20 with different players involved again so you need to compartmentalise that and Eoin Morgan is in the squad so of course there is a chance."