The former Celtic and Southampton left-back has suffered a recurrence of his groin problem and is unlikely to make a return until next month.
Kevin Blackwell has used Matthew Kilgallon in his position and then Danny Pugh for the win at Preston on Saturday.
"We were hoping to have Stephen back in training this week," said Blackwell. "He's been progressing well, but he has broken down again it looks like he could be another four or five weeks now which is disappointing."