A leading heart specialist recently stated that the midfielder, who suffered a cardiac arrest last month, could play football in half a year after he was discharged from the London Chest Hospital on Monday.
"I understand, because of the interest, that everybody thinks he's released from hospital so that's it, he's singing and dancing down the street, but people have got to understand there's room for continued improvement," said Coyle.
"But knowing Fabrice and how much of a battler he is, it wouldn't surprise me if he comes back. But I've got to stress he still needs that time with his family unit."
Meanwhile, Bolton are preparing to face Swansea City this weekend.