Andy Flower, England's director of cricket, has voiced concern that Kevin Pietersen will become detached from the rest of the England squad and will come to regret his decision to retire from limited-overs international cricket.

"Even Andrew Strauss found it difficult with only playing the Test game," Flower said. "Part of our challenges are to constantly work on our unity and harmony. It is a danger that he could become detached but I hope it is not the case."

Flower said that he tried in vain to dissuade Pietersen from a retirement from ODI cricket, which was announced on May 31, during discussions that had been ongoing for about 18 months.

England's most box-office batsman has made it clear that he would like to continue to play Twenty20 internationals, but this was refused because the terms of England's central contracts state that players must be available for both limited-overs formats to be considered for either.

"I think it's sad for Kevin that he won't be playing all three forms of the game in international cricket," Flower said. "I'm not annoyed. I think it's quite sad. He's very clear about what he wants to do, so that's his choice.

"He's a very fine international cricketer; he makes us stronger when he plays. I tried on a number of occasions to dissuade him for, what I believe, is his own good, but that's by the by. He makes his own decisions.

"I just thought that after you've retired from sport and you look back at your career he might think: 'Crikey, I wish I'd taken part in more World Cups and helped win the 2015 World Cup with England.' They are great memories and I think it's a little sad he won't get those opportunities anymore.

"He told me he didn't want to play one-day cricket anymore. We discussed it fully and the ECB explained very clearly what the ramifications were. He was aware he was on a contract. I don't know exactly what's been happening in his mind."

Flower countered Pietersen's justification for his one-day retirement that the international schedule had become too heavy by revealing that he would have been rested from the ODI series against West Indies anyway.

"Kevin was due to be rested for this one-day series with the West Indies. But I don't think resting him for the Australian one-day series and South African one-day series was an option. These are two of the best cricketing nations in the world and we want to put out strong sides against them."

The ECB's determination not to allow ODI cricket to be degraded - winning a global ODI tournament remains a top priority - and fear of a widespread withdrawal of players from 50-over cricket was the reason for their uncompromising insistence that England players must be available for both one-day formats.

"What is important is the reasons behind the ECB policy," Flower said. And the reasons behind that policy is that 50-over cricket is an integral part of the goals set that the ECB want the international team to achieve. For the first time they want them to win a 50-over World Cup competition. There's also the ICC Champions Trophy; that's also a clear goal of the ECB.

"There is also the status of ODI cricket, not only in this country but over the world, to take into consideration and when making these policy decisions you have to consider the precedents. And if that policy encourages five or six other top class international players to retire from international one-day cricket, you are degrading the status of ODI cricket in this country and the world."

Flower was reluctant to be drawn on England's heavy international schedule. "I think there's very limited influence I have on the schedule. The schedule is tough, there's no doubt about that. If you have been involved in that over a period of time it's tough. My job is to try and manage it as well as possible."

As he remarked, with reference to the debate that followed the resting of James Anderson and Stuart Broad from the third Test at Edgbaston, that was not always easy.

Flower denied that there was any problem with his own relationship with Pietersen. "I have read occasionally our relationship is not great, but actually I think we get on pretty well," he said. "We're fairly honest with each other and I think we have quite a good working relationship. I hope he can really enjoy the years of Test cricket that are ahead of him and I hope he does brilliantly in them.

"He's got his game into really good order at the moment. Technically he's really sound. He's done some great work with Mushtaq Ahmed and Graham Gooch on his batting, especially his playing of spin. His new method worked and you probably saw evidence of that on Sunday in the way he played their spinner."

Flower also confirmed that Pietersen will play four T20 games for Surrey - three at the Kia Oval and one at Hove - before playing one championship match against Lancashire at Guildford in preparation for the Investec Test series against South Africa. Flower also confirmed that talks about Andrew Strauss going on loan, probably to Somerset, had "been mooted".

"Between now and the South African Test series the amount of four-day cricket available to Strauss is non-existent," Flower said. "He's got one game before the Test series so it is a bit of a problem. How we deal with that is not that easy. Myself, Andrew Strauss and Graham Gooch have an idea about how we can do that but it's not ideal. It's tricky but no decisions have been made."

George Dobell is a senior correspondent at ESPNcricinfo