Andrew Strauss has said he knew Michael Yardy was struggling with depression before Yardy took the decision to withdraw from the World Cup and fly home.

Yardy became the fifth member of England's original squad to head home early and his departure inevitably drew comparison to Strauss's old opening partner Marcus Trescothick, who retired from international cricket five years ago after suffering stress-related illnesses. Since then England have had structures put in place to help players but they couldn't prevent Yardy from needing to leave the tournament early.

"It's a horrible thing for him to have to go through," Strauss said. "It's something he has been managing for a while and there have been systems in place to help him manage it but over the last week or so, it's got too much for him and he has had to go home."

Geoff Boycott sparked controversy shortly after the news of Yardy's departure surfaced when he suggested the depression had come from disappointing results on the field. "He must have been reading my comments about his bowling - it must have upset him," Boycott told BBC Radio Five Live. "Obviously it was too much for him at this level. If any blame is attached it's partly to the selectors because I'm sorry, he's not good enough at this level."

Strauss waved aside Boycott's remarks and said the squad were 'disappointed' when they heard them. "I think they showed a fundamental misunderstanding of the issue. I don't think your cricketing ability or what you have achieved has anything to do with it whatsoever.

"There are significant pressures, and as you get older a lot of us have kids and what not, which makes touring harder. It's important to draw attention to the fact that it's different having a hard time being away from home and actually suffering from depression. They are two very different things."

The schedule confronting England players has been a major talking point of their erratic campaign. Following their shock defeats to Ireland and Bangladesh in the group stages many suggested the team looked fatigued. Strauss, however, emphasised throughout that tiredness could not be blamed and said Yardy's condition was separate from the general demands of touring.

"Obviously if you are in a hotel room for five or six months one end, you're going to have days when you feel down," Strauss said. "I think that's very different from suffering from depression. International cricket is challenging in terms of how you are temperamentally equipped with spending long periods away from home. That's something we all go through. Depression is something completely different."

Despite the setback Strauss was confident Yardy's departure wouldn't distract the side ahead of their knockout match against Sri Lanka. "It's not difficult to focus our minds on this game of cricket. It's a must-win game of cricket. If we lose we are on the plane home. If we win we are in the World Cup semi-final. I think as players you get quite used to switching on and off when the situation demands it."