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 by referee Mark Clattenburg.
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 had a brief chance to assess the damage suffered by Di Santo, and explained it could be a bad blow. He 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."