Flintoff said that the lure of Twenty20 cricket around the world could be too much and that Pietersen might intend to focus on the short form of the game.
"I wouldn't read too much into his not playing New Zealand, Kevin will be ready for the Ashes," Flintoff told Sky Sports News.
"There are 10 Tests against Australia in the next few months - I expect England to win and expect Kevin to be part of that. I would be quite interested to see if Kevin tries to play Test cricket after that.
"We'll see what happens after that, if he is lured away to play IPL and Twenty20 cricket around the world. I've got a sneaking suspicion he'll be looking at those 10 Tests and then consider his future."
Pietersen has played in 92 Tests for England.