Wigan manager Roberto Martinez condemned Birmingham midfielder Craig Gardner's foul on Franco Di Santo and raised fears the Latics striker may have suffered ankle ligament damage.
Gardner went in on Di Santo with a foot raised in the final minute of a woeful goalless draw at St Andrew's and was given a straight red card. Birmingham's four-goal leading scorer will have to serve a three-match ban, but Di Santo could be out for longer if scans show serious damage.
Martinez said: "I've just seen Franco Di Santo's leg and that's my worry. We have to see the extent of that injury. He has a couple of nasty cuts in his leg and by that you can see the challenge was really high.
"The referee had a clear view and was on top of the incident and my worry is the extent of the injury. The cut swelled up straight away and there could be a bit of ligament damage in his ankle, which is the worry.
"From where I was, Gardner's leading foot was really high and he gets the ball with the second foot. Nowadays you can't go into a challenge like that with your feet high.
"It was a reckless challenge with excessive force and it was a red card, but all I'm worried about is Franco's injury."
Birmingham manager Alex McLeish had no complaints with the sending-off.
McLeish said: "At the time I just thought it was two players together and you couldn't avoid a collision but I've seen it on video and we won't be appealing.
"I don't think it was a massively dirty tackle but when your studs are showing, it's come more and more into the English game. You might have got away with it a year ago but, when there are studs colliding with a player's leg, then the refs are clamping down on that in this country.
"It's been in international football for a long time but as long as everyone is consistent I don't mind. The ref was in a good position and, under the rules, he's made the right decision."