Ireland played well in the first half and his miscued shot resulted in Darren Bent opening the scoring on 36 minutes.
“We need to have a look at him actually,” said boss Paul Lambert.
“It’s his arm he’s having a problem with at the minute. I don’t know if it would be a fracture, that’s the fear of it.
“It was caused during the game. He’s a good player, Stephen. The first half I thought we were a threat and he was at the forefront of it. It’s a blow when you lose any player but I’ll just have to wait and see how his injury is.
“I think there will be an X-ray and the doctor and physios will let me know what’s happening.
“I don’t know exactly. He’s got his arm in a sling at the minute.”