The 32-year-old batsman, originally dropped for sending "provocative" texts to South Africa players, was yesterday added to the touring party for this winter's trip to the subcontinent after reconciling with the ECB.
Flintoff, who played with and captained Pietersen during his England career, predicts that 'KP' will once again prove his worth when his back is against the wall.
"I think [captain] Alastair Cook might benefit from this. He might get KP at his best," Flintoff told BBC Sport.
"When Kevin's got a point to prove he usually proves it with the bat. When people get on his case he comes out swinging and scores runs.
"We saw that when he came into the international game in South Africa and he just kept scoring hundreds. In his last innings, he got a hundred at Headingley and saved England."
England will face India in four Test matches, beginning in Ahmedabad on November 14.