The 30-year-old is said to be returning to training today and is likely to be fined for his absence.
"Without a doubt he will be facing a fine," said manager Steve Kean.
"He will face a disciplinary when he comes in, we'll discuss that with him and his representatives and we will see what the way forward is."
Kean also said that the forward would not be joining the club in Hong Kong for their participation in the Premier League Trophy.
The Senegalese striker spent the second half of last season on loan at Rangers, helping them to a league and cup double.