Pietersen averages more than 50 from 29 Test appearances

The batsman, 27, was confined to his hotel room the day before with a high temperature and was on antibiotics.

There were fears he might miss his first Test since making his debut in 2005 but those have now been allayed.

"He's fine. He had a virus and it was a bit more of a concern on Wednesday but he seems to have pulled through pretty well," captain Michael Vaughan said.

"He didn't take part in the more phsycial side of the fielding drills but he's had a long bat and says he's fine.

Since making his debut at Lord's against Australia, Pietersen averages more than 50 from 29 Test appearances.

It's a big relief for the team because he's such an important player Vaughan on Pietersen

He scored 203 runs in the first two Tests against India, with a century at Lord's but England trail 1-0 after losing at Trent Bridge.

"It was slightly worrying when I heard he'd got a virus but the doctor said straight away that as long as he got his tablets down him he'd be okay," Vaughan added.

"It's obviously better seeing him here having a bat and hearing his words saying he's fine. It's a big relief for the team because he's such an important player."

The hosts need a win to avoid their first home Test series defeat since 2001 and prevent India winning a series here for the first time in 21 years.

England are likely to name an unchanged side for the match after naming the same 12-man squad that has contested the series so far.