The Ashes: Kevin Pietersen winning fitness battle ahead of 3rd Test

England are optimistic Kevin Pietersen will be fit to play in the third Ashes Test against Australia at Manchester's Old Trafford ground starting Thursday.

Pietersen suffered a left calf injury during England's crushing 347-run win in the second Test at Lord's, which put the Ashes-holders 2-0 up in the five-match series with three to play.

Since then the 33-year-old Pietersen, arguably England's most talented batsman, has undergone an intensive programme to regain full fitness.

And while no final decision has yet been made on whether he will be in the third Test side, England captain Alastair Cook was upbeat about his chances when speaking to reporters at Old Trafford on Wednesday.

"(He is) pretty good. He's come through training the past two days and done everything that's been asked of him," Cook said.

"Clearly we have to make a decision tomorrow (Thursday) morning just in case he pulls up different to that, but we'll see and we're pretty hopeful.

"We don't know quite how he'll pull up from today's (Wednesday's) training, but he's worked incredibly hard with the medical team over the last week to get himself right, so fingers crossed he has."

South Africa-born Pietersen batted for 15 minutes on Wednesday as bad weather saw England train in Old Trafford's indoor nets.

He did go outside briefly for a trio of 30-yard shuttle runs on a damp outfield, but soon returned indoors with little to suggest he'd been hampered by his calf problem.

In a bid to further test his fitness, Pietersen had earlier taken the unusual step while batting in a net of sometimes setting off and running after playing a shot as he tried to replicate match conditions.

Former England captain Pietersen has missed most of the side's matches since a knee injury forced his early exit from the tour of New Zealand in March.

He was sidelined from all cricket until making a superb unbeaten 177 for Surrey in a County Championship match in June.

Pietersen was recalled by England for their washed out Twenty20 match against New Zealand at The Oval, his Surrey home ground, on June 27.

He then played in England's 14-run first Test win over Australia at Trent Bridge where he made scores of 14 and 64.

Although he's scored 7,584 runs in 96 Tests, including 22 hundreds, at an impressive average of nearly 50, Pietersen managed just seven runs in total across two innings at Lord's.

However, the fact England have managed to go 2-0 up in the Ashes without a major innings from Pietersen suggests they can cope without him.

Moreover Nottinghamshire's James Taylor, brought in as cover for Pietersen, made an unbeaten hundred guesting for Sussex against Australia in a tour match last weekend.