it would mean that lawyer is not going to represent him.
If you are asking why a lawyer would refuse to represent a person, that is different. It could be any number of reasons.
Maybe they know this person from someplace and felt they cannot represent the defendant properly due to something they know about the defendant. Maybe their grandma in Alaska took ill and they are going to see her.
Like I said, there a numerous reasons they could quit the case. I have no way of knowing which one it is.