A back spasm has rendered Jason Roy a doubt for England's first one-day international against South Africa in Bloemfontein on Wednesday.

The complaint prevented the opening batsman from taking part in yesterday's training session.

However, the 25-year-old is due to feature in the nets today, with a fitness test scheduled for tomorrow morning.

If Roy is unable to play, it is likely that either Joe Root or Moeen Ali will be moved to the top of the order.