The Hibs left-back hurt his ankle during the 1-0 victory in Ayrshire and was replaced by Josh Doig at the interval.
Medical staff put a protective moon boot on him and the Easter Road manager is now hoping the knock will not be too serious.
"It's just precautionary at the moment,” said Ross of Stevenson’s moon boot. “He rolled his ankle towards the end of the first half.
"The one thing about Lewis is that he's a proper warrior. If he's able to be fit, he will be, but we will see how he settles down between the next 24-48 hours.”
Stevenson has not been Hibs’ regular left-back this season, ceding his place to teenager Doig, but would be in contention to start Saturday’s semi-final against Hearts.