The 29-year old World Cup star played his first game in over a year when coming on as a substitute against Crystal Palace at the weekend and Allardyce says that although the ex-Auxerre and Club Brugge player has done well to make a successful comeback he must still prove he can do it at Premiership level.
"Khalilou has undergone a life-changing experience and shown huge desire to get back to where he is now.
"He has been with us for two months and has broken into the first team - but it is still too early to say whether he has the quality you need to be a Premiership player."