Blackburn suffered a double injury blow during their goalless draw with Millwall in the FA Cup sixth round tie at The Den.
Bradley Orr came on in the first half for Adam Henley after he suffered an injury but he himself had to be replaced 12 minutes later with a suspected broken rib following a challenge with Danny Shittu.
Scott Dann also had to have his head bandaged after being caught by Rob Hulse's elbow in the first half of a feisty clash.
"There were a lot of tackles flying around today and a couple of cheap shots going on out there, which is disappointing," said Appleton.
"Adam looks as if he has done his hamstring again, which is disappointing.
"Brad might have cracked a rib. He is really struggling with his breathing at the minute and is in a lot of pain.
"He is taking a lot of pain killers and we will get him scanned and X-rayed as soon as possible."