England's two-part tour to India ends with the fifth and final ODI on 27 January, and Pietersen's new four-month central contract covers all forms of the game.
Any decision over an extension - to make it a full-year contract - will be made by team director Andy Flower, who will also decide when the "reintegration" process is complete.
"I'd like to take this opportunity to apologise to my team-mates, all England supporters and the ECB for the situation that has arisen over the last couple of months," said Pietersen.
ECB's Clarke on Pietersen return
"Thankfully we have drawn a line under it and can move forward. Although it has been made clear in the statement, I'd like to make it clear that at no time did I share tactical information with any of the South Africans.
"I'm committed to completing the reintegration process we have agreed and representing England in all formats, hopefully until the World Cup in 2015 if my body allows.
"I want to see my son grow up seeing me play for England and hope one day he will put an England shirt on himself."
The statement said Pietersen had not retained the text messages, but gave a "binding assurance that, to the best of his recollection", they did not "convey any messages which were derogatory about the England captain, the England team director, the ECB or employees of the ECB".
ECB chairman Giles Clarke said he spent an "excellent" and "thoroughly constructive" two-and-a-half hours with Pietersen on Wednesday.
Pietersen's international record
v Australia (Lord's), 21 July 2005
88 matches, 151 innings, 7,076 runs, highest score 227, average 49.48, 27 fifties, 21 centuries
One-day international debut:
v Zimbabwe (Harare), 28 November 2004
127 matches, 116 innings, 4,184 runs, highest score 130, average 41.84, 23 fifties, nine centuries
T20 international debut:
v Australia (Southampton), 15 June 2005
T20 international record:
36 matches, 36 innings, 1,176 runs, highest score 79, average 37.93, seven fifties
"The issue is can Kevin Pietersen be allowed back in that dressing room?" said Vaughan.
"Now he has got a four-month trial period the only way to find out is to go into the dressing room, make a speech, get round with some of the players he has had issues with, have a beer, and try and iron it all out because you want to see the best players playing."
Pietersen averages almost 50 in Tests and, at his best, is one of the world's most prolific batsmen.
The dispute has been dragging on for more than four months after he announced his retirement from international limited-overs cricket in May before reversing that decision in August.
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