13 June,2012 09:03 AM IST | | AFP
Pietersen wanted to continue playing Twenty20s - he was man of the tournament when England won the 2010 World Twenty20 and was keen to help them defend their title in Sri Lanka in September - while abandoning 50-over one-day internationals (ODIs).
But Flower said England were right to deny Pietersen his wish as otherwise "five or six players" might have done the same thing.
"When Kevin told me he wanted to retire from one-day cricket I must have had three or four subsequent meetings with him where I tried to dissuade him from doing so," Flower told BBC's Test Match Special.
"I think it's really sad he won't be playing all three forms of the game. He's in incredible form - technically, he's excellent."
Flower, once a world-class batsman for Zimbabwe, said England had plans in place to give Pietersen a break if needed.
âKP can rest'
"He can rest - it's not as if KP can't ever rest - we do rest him, and if you look back at various series that's what we've done.
"He's also had significant chunks out with injury; it's not that he doesn't get a chance to rest."
As for Pietersen wanting to opt out of 50-over cricket, Flower said England cricketers knew the terms of their contracts.
"You can't choose between one of the limited-overs formats - it's there in black and white.
"Kevin is very clear that he doesn't want to play one-day cricket any more, so that makes him unavailable for Twenty20 cricket," said Flower.
"I hope that after he's retired he doesn't regret that, but that's the decision that's been taken."
England's first one-day series without Pietersen starts against the West Indies on Saturday. - u00a0