Jonathan Kodjia will be out for up to three weeks after fracturing his cheekbone.
Kodjia was involved in an innocuous training ground clash with Marvelous Nakamba.
Dean Smith confirmed the issue with Kodjia in his weekly interview with Club TV but didn’t at that stage know the extent of his injury.
However, after being assessed in hospital, the striker underwent an operation to correct the issue and will now spend some time on the sidelines.
He said: “Jonathan has fractured a cheekbone on the training ground.
“He just clashed heads with Marvelous in a non-competitive part of training.
"We thought it was fine but they picked up a fracture at the hospital and he’s had an operation which means he will be out for two-three weeks.
“He will come back initially non-contact and then we will have to see how he goes.
“We have seen a few of these injuries where masks are worn so we will certainly be looking at that longer down the line.”
Smith also confirmed that he’s hoping to have James Chester available to play in the same timeframe – two-three weeks.
He added: “He felt a hamstring in pre-season and it’s been a niggling one.
"But he’s back in training now and it’s a boost for all of us.
“He has Premier League experience and a lot of experience in the dressing room, too.”