"I would be amazed now if we don't keep Diop. It isn't signed but it's very close," said the boss.
Diop, 28, is set to return to the side this weekend against Sunderland. He has been away at the African Cup of nations and with injury as well has not made a full 90 minute appearance since November.
"It will be a little bit of a gamble because he hasn't played 90 minutes for us since the beginning of November," Coleman continued.
"I would be surprised if he plays the 90 minutes.
"It could be he starts and doesn't finish or we might bring him on later in the game.
"We need the points and it's got to the stage where we're having to take a bit of a chance on him even though he is lacking the match practice."