Pietersen confirmed that he would no longer play for England last Tuesday after the South Africa-born batsman was left out of the England squads for the tour of the Caribbean and the ICC World Twenty20.
At the time, the ECB would only cite the need for a new "team ethic and philosophy" in the wake of the 5-0 Test series defeat in Australia.
However, following calls for an explanation from players including former England captains Ian Botham and Michael Vaughan, the ECB issued a joint statement with the Professional Cricketers' Association.
"The ECB recognises the significant contribution Kevin has made to England teams over the last decade," the statement read.
"He has played some of the finest innings ever produced by an England batsman. However, the England team needs to rebuild after the whitewash in Australia.
"To do that we must invest in our captain Alastair Cook and we must support him in creating a culture in which we can be confident he will have the full support of all players, with everyone pulling in the same direction and able to trust each other.
"It is for those reasons that we have decided to move on without Kevin Pietersen."
Pietersen, 33, bowed out as England's record scorer across all formats of the game, with 13,797 runs to his name.
However, his strong personality made him a divisive presence in the England changing room.
He fell out with two head coaches in Peter Moores and Andy Flower and was also briefly dropped in 2012 after it emerged that he had sent text messages criticising then England captain Andrew Strauss to South African players.


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