The Ashes: James Tredwell ready to be the understudy for England's penultimate act

England may test the world supplies of cotton wool in which to wrap their key players before the Ashes. While their desire to win the Champions Trophy should not be underestimated they are anxiously aware of their tasks later in the summer.

Thus, the likelihood is that Graeme Swann will miss his third match of the tournament when England play their semi-final. In his case, influential though he is, they have become almost sanguine when he is missing from their one-day side. The risk of playing him given the looming assignments is greater than the risk of not playing him. James Tredwell, his limited-overs understudy, has made that call much easier to make.

England would not like to enter the fray against Australia without Swann, the most accomplished and incisive of all modern orthodox off-spinners. But when Tredwell takes over from him in the one-day side the patchwork is almost impossible to see.

In the win against New Zealand on Sunday, which confirmed England's place in the last four, Tredwell again bowled his rolling off-spin with skill and maturity. To concede 27 runs off four overs when the slog was on was a typically worthy effort. "I think I'm pretty lucky really," said Tredwell yesterday, reflecting on his role as an eternal second string. "I've played for my country and continue to be involved in the environment.

"Obviously it would be nice if Swanny wasn't around, I might get a few more opportunities. But equally to be compared to someone like him and the record he's got is a pretty proud achievement in its own right."

Tredwell has played 17 ODIs, usually as a replacement for Swann, though they have appeared three times in the same team, as they did in his solitary Test in Bangladesh three years ago. He has taken 26 wickets at 25.62 compared to Swann's 104 at 27.77.

Swann withdrew from the Champions Trophy match against Australia when he woke up with a sore back and was withdrawn equally late from the team to play New Zealand on Sunday when he experienced tightness in his calf.

In neither case was it more than a niggle but England are adhering to a strict policy that involves a delicate balancing act. Victory in the Champions Trophy was the first of their three major objectives this year – twin Ashes victories being the others – but it will not be done at the expense of what follows. As a result Tredwell had virtually no notice.

"If you prepare right before every game you're obviously physically prepared in terms of bowling in the nets and things like that," he said. "I guess, yes, it is a bit of a struggle if you don't know you're playing from one day to the next but it's one of those things you have to come up against and tackle it when it arrives. I've done okay so far, though, dealing with that." The wrap them in cotton wool policy was one reason the decision was made early that Kevin Pietersen would not be part of the squad for the competition. He is making his long-scheduled return for Surrey in the County Championship at Headingley on Friday.

In his characteristic fashion, Swann told anybody prepared to listen yesterday that he would be fit for the semi-final. But players' personal opinions may not be canvassed too widely at present. There is a feeling in the camp that they are ready for anything after progressing in a week that started with one of their players being hit by an opponent in a late-night bar, went on to see the team being accused of ball tampering and concluded with a must-win game that was ultimately closer than it should have been.

They went for a drink after the 10 run defeat of New Zealand on Sunday night, though it is understood they stayed clear of the Cardiff branch of the Walkabout bar. It was in its Birmingham establishment eight days earlier that Joe Root was punched by the Australian batsman, David Warner.

Tredwell said: "Obviously the eye is firmly on us now. I think the lads understand they've got to be careful, and although it's an important thing for a team to celebrate we don't want more things coming up on the team because that could be damaging."