Kevin Pietersen has cured Shane Warne's selection headache - after being ruled out of this week's championship match against Lancashire.

Pietersen suffered a minor calf strain while fielding in his first Hampshire appearance for exactly a year against Ireland yesterday.

The 26-year-old still made an unbeaten 66 (71 balls) without the aid of a runner as the Hawks cruised to an eight-wicket win against the Irish with four balls to spare.

But he was not entirely comfortable while running between the wickets in putting on 143 in 23 overs with Sean Ervine.

That put what would have been only his seventh championship appearance for Hampshire - against a Lancashire side expected to include his England teammates Andrew Flintoff, James Anderson and Sajid Mahmood - in some doubt.

And this afternoon he was ruled out of the match by the England and Wales Cricket Board after undergoing an MRI scan.

The ECB medical staff will assess Pietersen's fitness again later in the week.

Pietersen should be be available for the first Test against the West Indies at Lord's on May 17 but Hampshire had expected him to make what would have been only his third championship appearance for the county at the Rose Bowl.

Last night, physio Andrew Nealon said: "We're in the process of arranging a precautionary scan but providing the news is good and reveals nothing serious he'll be fine for Wednesday."

Pietersen's withdrawal at least saves Warne the difficult decision of which batsman to leave out to accommodate the England star.

But Warne still has tough decisions to make with Chris Tremlett, Sean Ervine, Dimitri Mascarenhas all available.

He said: "Selection is very difficult at the moment. Trying to squeeze 14 players who should be playing first-class cricket into 11 is hard work, but we've always wanted to be in a position where we have to leave good players out.

"A squad will win us the championship, not 11 players. This is only our third game with another 13 still to go so we'll need players fresh.

"We'll be rotating and resting a few of the bowlers and certain conditions might mean certain players play rather than others but we've got that luxury."

Opening batsman Michael Carberry is close to returning after recovering from a knee injury but Michael Brown's successive hundreds have cemented his place alongside Jimmy Adams.

Shaun Udal is available after recovering from an ankle injury that was so bad he had to be stretchered from the field at the Brit Oval just ten days ago.

Udal has been dubbed "Lazarus" by Warne, but with the wicket expected to favour the seamers, he is expected to be afforded another week's rest.

With Tremlett now ready for four-day cricket after two FP Trophy games, James Tomlinson is likely to miss out.

Lancashire have their England coningent available but Warne wishes he was preparing for his first county championship duel with his great spin rival Muttiah Muralitharan, who does not play his first county game of the season until next week.

Warne continued: "We're all disappointed Murali's not playing, we were looking forward to both sides being at full strength - although a couple of our tail enders aren't as disappointed!"

Lancashire have available Flintoff and two other members of the England attack in Anderson and Mahmood as well as Brad Hodge, who, like Stuart Clark, has just returned from World Cup duty with Australia.

Lancashire beat Surrey by seven wickets at Old Trafford last week but are likely to leave out four from Iain Sutcliffe, Peter Horton, Tom Smith, Oliver Newby, Glenn Chapple and Cork to make way for Hodge, Flintoff, Anderson and Mahmood.

Warne added: "It'll be interesting to see whether Mahmood or Dominic Cork plays. If they have Sutcliffe, Chilton, Loye, Hodge, Law, Flintoff, Sutton, Chapple, Keedy and Anderson they've got a straight choice between Mahmood and Cork.

"Cork's obviously a key player for them so I'll be interested to see what they do."

Hampshire (probable): Adams, Brown, Crawley, Lumb, Benham, Pothas, Mascarenhas, Warne, Clark, Tremlett, Bruce.

Lancashire (from): Chilton, Sutcliffe, Loye, Hodge, Law, Horton, Flintoff, Sutton, Chapple, Keedy, Anderson, Mahmood, Cork, Newby, Smith.