Kevin Pietersen apologised on Wednesday for sending "provocative" text messages to South African players but team officials said it was too soon to say if he still had a future as an England player.
Last weekend, star batsman Pietersen was dramatically dropped from the squad for this week's third and final Test at Lord's, despite scoring a superb 149 in the drawn second Test at Headingley.
Pietersen was axed for failing to reveal the contents of those text messages, some of which were said to contain criticisms of England captain Andrew Strauss.
South Africa-born Pietersen, in an England and Wales Cricket Board (ECB) statement, admitted: "I did send what you might call provocative texts to my close friends in the SA team.
"The texts were meant as banter between close friends. I need to rein myself in sometimes. I apologise to Straussy and the team for the inappropriate remarks at the press conference and for the texts.
"I truly didn't mean to cause upset or tension particularly with important games at stake."
England managing director Hugh Morris said: "We are in receipt of Kevin's apology but further discussions need to take place to establish whether it is possible to regain the trust and mutual respect required to ensure all parties are able to focus on playing cricket and to maintain the unity of purpose that has served us so well in recent years.
"A successful conclusion to this process is required for Kevin Pietersen's potential selection in all forms of the game to be considered."
Strauss, for whom the match at Lord's, his Middlesex home ground, will be his 100th Test and 50th as captain, welcomed the apology as a "first step" but said issues of "trust and mutual respect" remained.
"It's a first step. But there's a lot more to investigate in all of this," the left-handed opener added.
"If there is a way forward the issues regarding trust and mutual respect have to be dealt with and it's not just a one-way process and we need to deal with those behind closed doors."
Strauss added it was impossible to say whether the 32-year-old Pietersen would play for England again.
"I'm not willing to state one way or another whether it's going to be possible or impossible on that matter.
"He is a world-class player and no-one will deny that, when he is playing well and happy in the dressing room he is a great asset but that's not where we are at the moment.
"The selectors made a brave and correct decision -- with the issues we need to resolve, it would have been untenable to have him in the squad."
South Africa captain Graeme Smith said England would miss Pietersen and denied his side had fanned the flames of the controversy.
"It is between Kevin and the ECB. People are trying to say we have been involved but our manager has made it clear throughout what has been going on.
"KP is a world class player... No doubt he is a big loss but obviously, there is a talent pool in English cricket, so whoever comes in we will respect in the same way we respect Kevin."
England go into the game starting Thursday 1-0 down in the three-match series and need to win if they are to prevent South Africa replacing them as the world's number one Test side.
Tensions between Pietersen, whose 21 Tests hundreds leave him one shy of England's all-time record, and the ECB have been escalating for months.
The former England captain retired from limited overs internationals after officials refused his wish to opt out of 50-over matches while still playing Twenty20s.
Then came an extraordinary press conference after he was named man-of-the-match at Headingley, where Pietersen speculated the match at Lord's might be his "last Test".
And last week, on the eve of the squad announcement for Lord's, he took to YouTube to insist he was now available to play for England in all formats.
While his apology came too late for him to be selected for the third Test, it may help him be included in England's squad for the defence of their World Twenty20 title in Sri Lanka next month, due to be announced Saturday.
He was England's man of the tournament when they became World Twenty20 champions in the Caribbean two years ago.
Pietersen averages nearly 50 in Tests and is one of the outstanding batsmen of his generation.
By contrast Jonathan Bairstow, set to replace him at Lord's, was dropped after playing his first three Tests against the West Indies earlier this season and has an average of under 13.