England to cover for Harmison
His withdrawal was announced after England's five-wicket Twenty20 defeat by Pakistan in Bristol on Monday - a match in which Harmison didn't play.
Ahead of the start of the five-match series against Pakistan, which begins on Wednesday with a day/night contest in Cardiff, an England statement said: "The England selectors will place a bowler on standby after the first one-day international in Cardiff, provided there are no further injuries to England's seam bowlers."
An England spokesman clarified the statement to say that were another England quick to be sidelined, a replacement would come into the squad straight away. Any replacement is likely to come from the 30-man squad named ahead of the Champions Trophy, so Graham Onions and Matthew Hoggard could be in the frame as well as Glen Chapple, if his C&G final appearance proved his fitness.
In Harmison's absence, England gave the new-ball to Darren Gough and Stuart Broad in Bristol - a combination they are likely to use again at Sophia Gardens.