Sven-Goran Eriksson is "optimistic" Wayne Rooney could play some part for England against Trinidad and Tobago.

Eriksson will not rule out the idea of Rooney returning against the Caribbean minnows in Nurnberg on Thursday.

Asked whether Rooney would appear, the England boss said: "I'm very optimistic, always. I'm born like that. We have to decide that day by day, to be honest."

Rooney (20) returned to full training last Thursday after a foot scan showed his broken metatarsal bone had healed.

But Manchester United boss Alex Ferguson will be furious if his striker does make his World Cup debut against Trinidad and Tobago.

Ferguson wanted Eriksson to keep Rooney under wraps until the knock-out stages of the World Cup but the pair did not agree. Instead, Eriksson said Rooney would play as soon as he was "match-fit".

The England boss promised to invite an independent expert to look at Rooney's fitness before he played.

This was an attempt to placate Ferguson and prove he was not taking an undue risk with the player's long-term fitness, but it is unlikely to soothe United's fury.

Rooney trained on Sunday, along with the other England players not heavily involved in Saturday's 1-0 win against Paraguay.   PA