The 23-year-old TP Mazembe central defender has been training with the Black Cats, and he has already played in a fixture behind closed doors.
O'Neill said: "He played a little game the other day, but he had a swollen knee before he came here and he had to come off in the game.
"That will stop him training for a week at most. And then he'll be going away to play during the international break so we'll monitor him during that game.
"But I haven't seen enough of him yet to make a decision on him."