Northern Ireland are likely to be without Derby County striker Jamie Ward for the World Cup qualifier against Portugal later this month.
Ward has a torn hamstring and Derby manager Nigel Clough told the club's website that the striker will be out for a couple of weeks.
"He has an outside chance of being available for the Blackburn game on 20 October," said Clough.
Northern Ireland face Portugal in Porto on 16 October.
Ward started in the opening 2-0 defeat by Russia and then came on as a second-half substitute in the 1-1 home draw against Luxembourg.
Rangers pair Dean Shiels and Andrew Little are expected to be available as they are reported to be recovering well from injuries.
Northern Ireland manager Michael O'Neill will name his squad on Friday.