The number four batsman missed the recent Test series against New Zealand with a knee injury and has only recently returned to action for both county and country.
"We're definitely a better team for Kevin's inclusion," said the bowler. "He's just an extraordinary player. There's not really any down side at the minute.
"We saw it this week in the match at Chelmsford. I know he only got 49, but it just seemed far too easy for him.
"He seemed in great form. An in-form Kevin Pietersen is vital to our team going forward."
The first of five Tests between England and Australia will start on Wednesday morning at Trent Bridge.