Northern Ireland boss Michael O'Neill is likely to be without Will Grigg for the World Cup qualifiers against Russia and Israel.
The in-form Walsall striker made his first international start in the goalless draw in Malta last month, and was expected to lead the line against Russia in the absence of the suspended Kyle Lafferty.
But the 21-year-old was unable to train on Wednesday due to a hamstring problem and is now a major doubt for Belfast double header.
O'Neill, still chasing his first win at the helm, has a number of options in attack, but none of his charges have a proven record at international level.
Inverness forward Billy McKay and Aberdeen pair Niall McGinn and Josh Magennis are both available for selection though.