The former Hampshire batsman has spent three weeks with the Delhi Daredevils before starting preparations for England's summer programme by playing for Surrey in their LV= County Championship clash against Worcestershire at New Road from today.
The Division One encounter represents Pietersen's only first-class action before England face West Indies in next week's first Test at Lord's.
But the 31-year-old has no qualms about taking part in the lucrative IPL and is confident about adjusting to the early season conditions batsman have to confront in this country.
He said: "It's plain and simple. I'm sick and tired of having to defend myself about going to the IPL every year.
"I don't see why I need to defend myself. It's something that's there which all the best players in the world play in. There is no need to defend myself.
"Someone in the Indian media asked about ex-players talking about whether it's a good idea for me to play in India.
"Every single time in March and April, I have to defend myself about going to India.
"But it's not going to change, I will play in the IPL, it's the best tournament going, and that's the way it is."
He was confined to fielding duties on a rain-hit first day at New Road as Worcestershire reached 56 without loss.
But Pietersen, who looked in marvellous touch when his innings of 151 helped England secure their only Test win of the winter against Sri Lanka in Colombo last month, claimed: "I feel like I've never batted better.
"I feel in great nick at the moment but everyone knows you have a couple of bad scores and everyone says you are in bad nick again.
"I know that is not true but all I'm doing at the moment is concentrating on my batting, doing whatever I can do to influence a fixture here in Worcester.
"I'm at the stage of my career now where that's all I want to do, just influence games positively and play to the requirements of the team and whatever happens, happens."
A cold and rainy New Road is in stark contrast to the temperatures Pietersen has been experiencing in India but is adamant adapting to such conditions is part of the challenge.
The only downside is Pietersen will not be at home for son Dylan's second birthday tomorrow although he is hoping to make an appearance should rain persist at Worcester.
He said: "It is different conditions. It's 15 degrees. I'd like to see a two in front of the five! But it's not a case of adapting to different conditions.
"I've been in England for 13 years now. It's just adjusting. When you go to Sri Lanka and its 44-45 degrees, you have to adjust then as well. There are no dramas.
"I love doing what I'm doing. I'm as fit as a fiddle. There is nothing wrong with my fitness at the moment. I love my job and there is nothing else I would rather be doing.
"This week makes it very tough for me because I've been away for two months and haven't seen my kid for two months and it's his birthday tomorrow.
"It's not the best situation for me but this is my job, this is what I've got to do, my family realises that and it doesn't last forever.
"It's a case of, if the rain falls tomorrow, I'll be going back to London for a day."
Pietersen made it clear he wants to continue playing international cricket for the foreseeable future.
He said: "I'll play as long as I'm fit. I'm not going to play until 40! I'm going to play as long as I can. I love playing for England.
It's the best.
"Everyone says it's a shame missing out on the IPL for the rest of the series. Yes it is, but I'm playing the best form of cricket next week.
"I'm playing in a Test match at Lord's. Growing up as a kid, that's the sort of thing you dream of."